diff --git a/command.py b/command.py
index 4dbe2e7..5789582 100644
--- a/command.py
+++ b/command.py
@@ -70,7 +70,7 @@ class Command(object):
 
     groups = mp.config.GetString('manifest.groups')
     if not groups:
-      groups = 'default,platform-' + platform.system().lower()
+      groups = 'all,-notdefault,platform-' + platform.system().lower()
     groups = [x for x in re.split('[,\s]+', groups) if x]
 
     if not args:
diff --git a/docs/manifest-format.txt b/docs/manifest-format.txt
index 338e021..f499868 100644
--- a/docs/manifest-format.txt
+++ b/docs/manifest-format.txt
@@ -184,11 +184,12 @@ the default element is used.
 
 Attribute `groups`: List of groups to which this project belongs,
 whitespace or comma separated.  All projects belong to the group
-"default", and each project automatically belongs to a group of
-it's name:`name` and path:`path`.  E.g. for
+"all", and each project automatically belongs to a group of
+its name:`name` and path:`path`.  E.g. for
 <project name="monkeys" path="barrel-of"/>, that project
 definition is implicitly in the following manifest groups:
-default, name:monkeys, and path:barrel-of.
+default, name:monkeys, and path:barrel-of.  If you place a project in the
+group "notdefault", it will not be automatically downloaded by repo.
 
 Element annotation
 ------------------
diff --git a/manifest_xml.py b/manifest_xml.py
index 205e4af..65b7637 100644
--- a/manifest_xml.py
+++ b/manifest_xml.py
@@ -130,7 +130,7 @@ class XmlManifest(object):
 
     groups = mp.config.GetString('manifest.groups')
     if not groups:
-      groups = 'default'
+      groups = 'all'
     groups = [x for x in re.split(r'[,\s]+', groups) if x]
 
     doc = xml.dom.minidom.Document()
@@ -211,7 +211,7 @@ class XmlManifest(object):
         ce.setAttribute('dest', c.dest)
         e.appendChild(ce)
 
-      default_groups = ['default', 'name:%s' % p.name, 'path:%s' % p.relpath]
+      default_groups = ['all', 'name:%s' % p.name, 'path:%s' % p.relpath]
       egroups = [g for g in p.groups if g not in default_groups]
       if egroups:
         e.setAttribute('groups', ','.join(egroups))
diff --git a/project.py b/project.py
index 06baccb..60633b7 100644
--- a/project.py
+++ b/project.py
@@ -632,20 +632,21 @@ class Project(object):
     """Returns true if the manifest groups specified at init should cause
        this project to be synced.
        Prefixing a manifest group with "-" inverts the meaning of a group.
-       All projects are implicitly labelled with "default".
+       All projects are implicitly labelled with "all".
 
        labels are resolved in order.  In the example case of
-       project_groups: "default,group1,group2"
+       project_groups: "all,group1,group2"
        manifest_groups: "-group1,group2"
        the project will be matched.
     """
-    if self.groups is None:
-      return True
+    expanded_manifest_groups = manifest_groups or ['all', '-notdefault']
+    expanded_project_groups = ['all'] + (self.groups or [])
+
     matched = False
-    for group in manifest_groups:
-      if group.startswith('-') and group[1:] in self.groups:
+    for group in expanded_manifest_groups:
+      if group.startswith('-') and group[1:] in expanded_project_groups:
         matched = False
-      elif group in self.groups:
+      elif group in expanded_project_groups:
         matched = True
 
     return matched
diff --git a/subcmds/init.py b/subcmds/init.py
index b16f57c..9a4f711 100644
--- a/subcmds/init.py
+++ b/subcmds/init.py
@@ -90,12 +90,12 @@ to update the working directory files.
                  dest='depth',
                  help='create a shallow clone with given depth; see git clone')
     g.add_option('-g', '--groups',
-                 dest='groups', default='default',
+                 dest='groups', default='all,-notdefault',
                  help='restrict manifest projects to ones with a specified group',
                  metavar='GROUP')
     g.add_option('-p', '--platform',
                  dest='platform', default='auto',
-                 help='restrict manifest projects to ones with a specified'
+                 help='restrict manifest projects to ones with a specified '
                       'platform group [auto|all|none|linux|darwin|...]',
                  metavar='PLATFORM')
 
@@ -164,7 +164,7 @@ to update the working directory files.
 
     groups = [x for x in groups if x]
     groupstr = ','.join(groups)
-    if opt.platform == 'auto' and groupstr == 'default,platform-' + platform.system().lower():
+    if opt.platform == 'auto' and groupstr == 'all,-notdefault,platform-' + platform.system().lower():
       groupstr = None
     m.config.SetString('manifest.groups', groupstr)