diff --git a/mercurial/commands.py b/mercurial/commands.py
--- a/mercurial/commands.py
+++ b/mercurial/commands.py
@@ -472,14 +472,7 @@ def annotate(ui, repo, *pats, **opts):
             return bcache[rev]
         except KeyError:
             cl = repo.changelog.read(repo.changelog.node(rev))
-            name = cl[1]
-            f = name.find('@')
-            if f >= 0:
-                name = name[:f]
-            f = name.find('<')
-            if f >= 0:
-                name = name[f+1:]
-            bcache[rev] = name
+            bcache[rev] = name = ui.shortuser(cl[1])
             return name
 
     if not pats:
diff --git a/mercurial/hgweb.py b/mercurial/hgweb.py
--- a/mercurial/hgweb.py
+++ b/mercurial/hgweb.py
@@ -507,14 +507,7 @@ class hgweb:
                     name = bcache[r]
                 except KeyError:
                     cl = self.repo.changelog.read(cnode)
-                    name = cl[1]
-                    f = name.find('@')
-                    if f >= 0:
-                        name = name[:f]
-                    f = name.find('<')
-                    if f >= 0:
-                        name = name[f+1:]
-                    bcache[r] = name
+                    bcache[r] = name = self.repo.ui.shortuser(cl[1])
 
                 if last != cnode:
                     parity = 1 - parity
diff --git a/mercurial/ui.py b/mercurial/ui.py
--- a/mercurial/ui.py
+++ b/mercurial/ui.py
@@ -78,6 +78,16 @@ class ui:
                                 os.environ.get("USERNAME", "unknown"))
                  + '@' + socket.getfqdn()))
 
+    def shortuser(self, user):
+        """Return a short representation of a user name or email address."""
+        f = user.find('@')
+        if f >= 0:
+            user = user[:f]
+        f = user.find('<')
+        if f >= 0:
+            user = user[f+1:]
+        return user
+
     def expandpath(self, loc):
         paths = {}
         for name, path in self.configitems("paths"):