<% User.sitelist %>
macro renders the sites the user is a member of or has subscribed to in order of their last update-timestamp

Sourcecode in User/macros.js:
1:   function sitelist_macro(param) {
2:      var memberships = session.user.list();
3:      memberships.sort(new Function("a", "b", "return b.site.lastupdate - a.site.lastupdate"));
4:      for (var i in memberships) {
5:         var site = memberships[i].site;
6:         if (!site)
7:            continue;
8:         site.renderSkin("preview");
9:      }
10:     return;
11:  }