Some activity items do not contain time stamps

Now that I've written Timeago I think the best solution is to override theme_facebook_status_time() like this:

function activity_log_facebook_status_time($time) {
  if (!$time) {
    return FALSE;
  }
  if (module_exists('timeago')) {
    return timeago_format_date($time, format_date($time, 'small'));
  }
  return format_date($time, 'small');
}

Then using Timeago should be recommended on the project page.

Additionally we need to add a token that uses the function expressed above for group joins, relationship requests, and nodes (a Timeago token already exists for nodes, although we don't want to depend on it) -- and we need to add that token to the activity message templates.

Explanation of what this issue is about

Note that I just committed Timeago integration to FBSS and by default activity messages about status updates are not cached in Activity Log, so users who have Timeago installed will start seeing this work immediately for status updates.