diff --git a/database/database.go b/database/database.go
index d545184..d0c827d 100644
--- a/database/database.go
+++ b/database/database.go
@@ -601,6 +601,21 @@
 func (db *Database) Delete(path string) error {
 	c := db.Pool.Get()
 	defer c.Close()
+
+	if GAESearch {
+		ctx := bgCtx()
+		id, err := redis.String(c.Do("HGET", "ids", path))
+		if err == redis.ErrNil {
+			return nil
+		}
+		if err != nil {
+			return err
+		}
+		if err := deleteIndex(ctx, id); err != nil {
+			return err
+		}
+	}
+
 	_, err := deleteScript.Do(c, path)
 	return err
 }
diff --git a/database/indexae.go b/database/indexae.go
index 92f6fc2..4259025 100644
--- a/database/indexae.go
+++ b/database/indexae.go
@@ -172,6 +172,14 @@
 		unicode.IsSymbol(r)
 }
 
+func deleteIndex(c context.Context, id string) error {
+	idx, err := search.Open("packages")
+	if err != nil {
+		return err
+	}
+	return idx.Delete(c, id)
+}
+
 // PurgeIndex deletes all the packages from the search index.
 func PurgeIndex(c context.Context) error {
 	idx, err := search.Open("packages")
diff --git a/database/indexae_test.go b/database/indexae_test.go
index 6c5ee0e..42530d7 100644
--- a/database/indexae_test.go
+++ b/database/indexae_test.go
@@ -77,6 +77,7 @@
 		ImportCount: 1,
 		Fork:        true,
 		Stars:       10,
+		Score:       0.99,
 	}
 	if got != wanted {
 		t.Errorf("PutIndex got %v, want %v", got, wanted)
diff --git a/gddo-server/crawl.go b/gddo-server/crawl.go
index fb23fa7..6fd960d 100644
--- a/gddo-server/crawl.go
+++ b/gddo-server/crawl.go
@@ -61,7 +61,7 @@
 			}
 			pdoc = nil
 			err = gosrc.NotFoundError{Message: "no Go files or subdirs"}
-		} else if err != gosrc.ErrNotModified {
+		} else if _, ok := err.(gosrc.NotModifiedError); !ok {
 			pdoc = pdocNew
 		}
 	}
@@ -75,27 +75,54 @@
 		nextCrawl = start.Add(*maxAge * 30)
 	}
 
-	switch {
-	case err == nil:
+	if err == nil {
 		message = append(message, "put:", pdoc.Etag)
 		if err := db.Put(pdoc, nextCrawl, false); err != nil {
 			log.Printf("ERROR db.Put(%q): %v", importPath, err)
 		}
 		return pdoc, nil
-	case err == gosrc.ErrNotModified:
+	} else if e, ok := err.(gosrc.NotModifiedError); ok {
+		if !pdoc.IsCmd && isInactivePkg(importPath, e.Since) {
+			message = append(message, "delete inactive")
+			if err := db.Delete(importPath); err != nil {
+				log.Printf("ERROR db.Delete(%q): %v", importPath, err)
+			}
+			return nil, e
+		}
+		// Touch the package without updating and move on to next one.
 		message = append(message, "touch")
 		if err := db.SetNextCrawlEtag(pdoc.ProjectRoot, pdoc.Etag, nextCrawl); err != nil {
 			log.Printf("ERROR db.SetNextCrawlEtag(%q): %v", importPath, err)
 		}
 		return pdoc, nil
-	case gosrc.IsNotFound(err):
-		message = append(message, "notfound:", err)
+	} else if err == gosrc.ErrQuickFork {
+		message = append(message, "delete", err)
 		if err := db.Delete(importPath); err != nil {
 			log.Printf("ERROR db.Delete(%q): %v", importPath, err)
 		}
 		return nil, err
-	default:
+	} else if e, ok := err.(gosrc.NotFoundError); ok {
+		message = append(message, "notfound:", e)
+		if err := db.Delete(importPath); err != nil {
+			log.Printf("ERROR db.Delete(%q): %v", importPath, err)
+		}
+		return nil, e
+	} else {
 		message = append(message, "ERROR:", err)
 		return nil, err
 	}
 }
+
+// isInactivePkg reports whether the specified package is not imported
+// and has not been modified in 2 years.
+func isInactivePkg(pkg string, lastCommitted time.Time) bool {
+	if lastCommitted.IsZero() ||
+		time.Now().Before(lastCommitted.Add(2*365*24*time.Hour)) {
+		return false
+	}
+	n, err := db.ImporterCount(pkg)
+	if err != nil {
+		log.Printf("ERROR db.ImporterCount(%q): %v", pkg, err)
+	}
+	return n == 0
+}
diff --git a/gosrc/bitbucket.go b/gosrc/bitbucket.go
index c89feb3..76cea46 100644
--- a/gosrc/bitbucket.go
+++ b/gosrc/bitbucket.go
@@ -7,6 +7,7 @@
 package gosrc
 
 import (
+	"log"
 	"net/http"
 	"path"
 	"regexp"
@@ -34,6 +35,11 @@
 	IsFork    bool `json:"is_fork"`
 }
 
+type bitbucketNode struct {
+	Node      string `json:"node"`
+	Timestamp string `json:"utctimestamp"`
+}
+
 func getBitbucketDir(client *http.Client, match map[string]string, savedEtag string) (*Directory, error) {
 	var repo *bitbucketRepo
 	c := &httpClient{client: client}
@@ -50,27 +56,35 @@
 	}
 
 	tags := make(map[string]string)
+	timestamps := make(map[string]time.Time)
+
 	for _, nodeType := range []string{"branches", "tags"} {
-		var nodes map[string]struct {
-			Node string
-		}
+		var nodes map[string]bitbucketNode
 		if _, err := c.getJSON(expand("https://api.bitbucket.org/1.0/repositories/{owner}/{repo}/{0}", match, nodeType), &nodes); err != nil {
 			return nil, err
 		}
 		for t, n := range nodes {
 			tags[t] = n.Node
+			const timeFormat = "2006-01-02 15:04:05Z07:00"
+			committed, err := time.Parse(timeFormat, n.Timestamp)
+			if err != nil {
+				log.Println("error parsing timestamp:", n.Timestamp)
+				continue
+			}
+			timestamps[t] = committed
 		}
 	}
 
 	var err error
-	match["tag"], match["commit"], err = bestTag(tags, defaultTags[match["vcs"]])
+	tag, commit, err := bestTag(tags, defaultTags[match["vcs"]])
 	if err != nil {
 		return nil, err
 	}
-
+	match["tag"] = tag
+	match["commit"] = commit
 	etag := expand("{vcs}-{commit}", match)
 	if etag == savedEtag {
-		return nil, ErrNotModified
+		return nil, NotModifiedError{Since: timestamps[tag]}
 	}
 
 	if repo == nil {
diff --git a/gosrc/github.go b/gosrc/github.go
index ad8f4a3..49a00df 100644
--- a/gosrc/github.go
+++ b/gosrc/github.go
@@ -38,6 +38,15 @@
 	ownerRepoPat        = regexp.MustCompile(`^https://api.github.com/repos/([^/]+)/([^/]+)/`)
 )
 
+type githubCommit struct {
+	ID     string `json:"sha"`
+	Commit struct {
+		Committer struct {
+			Date time.Time `json:"date"`
+		} `json:"committer"`
+	} `json:"commit"`
+}
+
 func gitHubError(resp *http.Response) error {
 	var e struct {
 		Message string `json:"message"`
@@ -52,53 +61,34 @@
 
 	c := &httpClient{client: client, errFn: gitHubError}
 
-	type refJSON struct {
-		Object struct {
-			Type string
-			Sha  string
-			URL  string
-		}
-		Ref string
-		URL string
+	var repo struct {
+		Fork      bool      `json:"fork"`
+		Stars     int       `json:"stargazers_count"`
+		CreatedAt time.Time `json:"created_at"`
+		PushedAt  time.Time `json:"pushed_at"`
 	}
-	var refs []*refJSON
 
-	resp, err := c.getJSON(expand("https://api.github.com/repos/{owner}/{repo}/git/refs", match), &refs)
-	if err != nil {
+	if _, err := c.getJSON(expand("https://api.github.com/repos/{owner}/{repo}", match), &repo); err != nil {
 		return nil, err
 	}
 
-	// If the response contains a Link header, then fallback to requesting "master" and "go1" by name.
-	if resp.Header.Get("Link") != "" {
-		var masterRef refJSON
-		if _, err := c.getJSON(expand("https://api.github.com/repos/{owner}/{repo}/git/refs/heads/master", match), &masterRef); err == nil {
-			refs = append(refs, &masterRef)
-		}
-
-		var go1Ref refJSON
-		if _, err := c.getJSON(expand("https://api.github.com/repos/{owner}/{repo}/git/refs/tags/go1", match), &go1Ref); err == nil {
-			refs = append(refs, &go1Ref)
-		}
+	var commits []*githubCommit
+	url := expand("https://api.github.com/repos/{owner}/{repo}/commits", match)
+	url += fmt.Sprintf("?since=%s", repo.CreatedAt.Format(time.RFC3339))
+	if match["dir"] != "" {
+		url += fmt.Sprintf("&path=%s", match["dir"])
 	}
-
-	tags := make(map[string]string)
-	for _, ref := range refs {
-		switch {
-		case strings.HasPrefix(ref.Ref, "refs/heads/"):
-			tags[ref.Ref[len("refs/heads/"):]] = ref.Object.Sha
-		case strings.HasPrefix(ref.Ref, "refs/tags/"):
-			tags[ref.Ref[len("refs/tags/"):]] = ref.Object.Sha
-		}
-	}
-
-	var commit string
-	match["tag"], commit, err = bestTag(tags, "master")
-	if err != nil {
+	if _, err := c.getJSON(url, &commits); err != nil {
 		return nil, err
 	}
-
-	if commit == savedEtag {
-		return nil, ErrNotModified
+	if repo.Fork && isQuickFork(commits, repo.CreatedAt) {
+		return nil, ErrQuickFork
+	}
+	if len(commits) == 0 {
+		return nil, NotFoundError{Message: "package directory changed or removed"}
+	}
+	if commits[0].ID == savedEtag {
+		return nil, NotModifiedError{Since: commits[0].Commit.Committer.Date}
 	}
 
 	var contents []*struct {
@@ -108,7 +98,7 @@
 		HTMLURL string `json:"html_url"`
 	}
 
-	if _, err := c.getJSON(expand("https://api.github.com/repos/{owner}/{repo}/contents{dir}?ref={tag}", match), &contents); err != nil {
+	if _, err := c.getJSON(expand("https://api.github.com/repos/{owner}/{repo}/contents{dir}", match), &contents); err != nil {
 		// The GitHub content API returns array values for directories
 		// and object values for files. If there's a type mismatch at
 		// the beginning of the response, then assume that the path is
@@ -157,25 +147,14 @@
 
 	browseURL := expand("https://github.com/{owner}/{repo}", match)
 	if match["dir"] != "" {
-		browseURL = expand("https://github.com/{owner}/{repo}/tree/{tag}{dir}", match)
-	}
-
-	var repo = struct {
-		Fork      bool      `json:"fork"`
-		Stars     int       `json:"stargazers_count"`
-		CreatedAt time.Time `json:"created_at"`
-		PushedAt  time.Time `json:"pushed_at"`
-	}{}
-
-	if _, err := c.getJSON(expand("https://api.github.com/repos/{owner}/{repo}", match), &repo); err != nil {
-		return nil, err
+		browseURL = expand("https://github.com/{owner}/{repo}/tree{dir}", match)
 	}
 
 	isDeadEndFork := repo.Fork && repo.PushedAt.Before(repo.CreatedAt)
 
 	return &Directory{
 		BrowseURL:      browseURL,
-		Etag:           commit,
+		Etag:           commits[0].ID,
 		Files:          files,
 		LineFmt:        "%s#L%d",
 		ProjectName:    match["repo"],
@@ -189,6 +168,24 @@
 	}, nil
 }
 
+// isQuickFork reports whether the repository is a "quick fork":
+// it has fewer than 3 commits, all within a week of the repo creation, createdAt.
+func isQuickFork(commits []*githubCommit, createdAt time.Time) bool {
+	if len(commits) > 2 {
+		return false
+	}
+	oneWeekOld := createdAt.Add(7 * 24 * time.Hour)
+	if oneWeekOld.After(time.Now()) {
+		return false // a newborn baby of a repository
+	}
+	for _, commit := range commits {
+		if commit.Commit.Committer.Date.After(oneWeekOld) {
+			return false
+		}
+	}
+	return true
+}
+
 func getGitHubPresentation(client *http.Client, match map[string]string) (*Presentation, error) {
 	c := &httpClient{client: client, header: gitHubRawHeader}
 
@@ -310,7 +307,7 @@
 	commit := gist.History[0].Version
 
 	if commit == savedEtag {
-		return nil, ErrNotModified
+		return nil, NotModifiedError{}
 	}
 
 	var files []*File
diff --git a/gosrc/golang.go b/gosrc/golang.go
index f3d474d..faed15a 100644
--- a/gosrc/golang.go
+++ b/gosrc/golang.go
@@ -23,12 +23,6 @@
 
 	browseURL := "https://golang.org/src/" + importPath + "/"
 	p, err := c.getBytes(browseURL)
-	if IsNotFound(err) {
-		// Fallback to Go 1.3 directory structure.
-		// TODO(garyburd): Delete fallback after 1.4 is pushed to golang.org.
-		browseURL = "https://golang.org/src/pkg/" + importPath + "/"
-		p, err = c.getBytes(browseURL)
-	}
 	if err != nil {
 		return nil, err
 	}
@@ -40,7 +34,7 @@
 	}
 	etag = strings.Trim(string(m[1]), ". ")
 	if etag == savedEtag {
-		return nil, ErrNotModified
+		return nil, NotModifiedError{}
 	}
 
 	var files []*File
diff --git a/gosrc/google.go b/gosrc/google.go
index 1a47b59..3a2fc36 100644
--- a/gosrc/google.go
+++ b/gosrc/google.go
@@ -75,7 +75,7 @@
 	}
 	etag = expand("{vcs}-{0}", match, string(m[1]))
 	if etag == savedEtag {
-		return nil, ErrNotModified
+		return nil, NotModifiedError{}
 	}
 
 	var subdirs []string
diff --git a/gosrc/gosrc.go b/gosrc/gosrc.go
index b30c360..df33ee1 100644
--- a/gosrc/gosrc.go
+++ b/gosrc/gosrc.go
@@ -16,6 +16,7 @@
 	"path"
 	"regexp"
 	"strings"
+	"time"
 )
 
 // File represents a file.
@@ -112,8 +113,15 @@
 	return e.err.Error()
 }
 
-// ErrNotModified indicates that the directory matches the specified etag.
-var ErrNotModified = errors.New("package not modified")
+type NotModifiedError struct {
+	Since time.Time
+}
+
+func (e NotModifiedError) Error() string {
+	return fmt.Sprintf("package not modified since %s", e.Since.Format(time.RFC1123))
+}
+
+var ErrQuickFork = errors.New("package is a quick bug-fix fork")
 
 var errNoMatch = errors.New("no match")
 
diff --git a/gosrc/launchpad.go b/gosrc/launchpad.go
index 5cda037..3d561c8 100644
--- a/gosrc/launchpad.go
+++ b/gosrc/launchpad.go
@@ -119,7 +119,7 @@
 	hash = m.Sum(hash[:0])
 	etag := hex.EncodeToString(hash)
 	if etag == savedEtag {
-		return nil, ErrNotModified
+		return nil, NotModifiedError{}
 	}
 
 	return &Directory{
diff --git a/gosrc/vcs.go b/gosrc/vcs.go
index 6fbb545..bd7cc06 100644
--- a/gosrc/vcs.go
+++ b/gosrc/vcs.go
@@ -148,7 +148,7 @@
 	etag := scheme + "-" + commit
 
 	if etag == savedEtag {
-		return "", "", ErrNotModified
+		return "", "", NotModifiedError{}
 	}
 
 	dir := filepath.Join(TempDir, repo+".git")
@@ -201,7 +201,7 @@
 
 	etag := scheme + "-" + revno
 	if etag == savedEtag {
-		return "", "", ErrNotModified
+		return "", "", NotModifiedError{}
 	}
 
 	dir := filepath.Join(TempDir, repo+".svn")