Hi there,
This may be the wrong place for this discussion, but I members of this group will have expertise far beyond mine.
I'm running the Pantheon stack on the recommendation of some very helpful consultants, but I have some gaps in understanding on how the whole thing works. I've never quite understood, for example, why the number of "anonymous" users in the corner of the Admin Menu typically floats around 12-14, when with the Merury/Pressflow stuff turned off, the number is always higher.
That's not a big deal really, but yesterday I had to un-comment the "cookie domain" line in settings.php for the fckeditor file uploader to work right, and now the number of "anonymous" users is steadily close to 0. Also, Google Analytics is showing that we've had about half the hits to our site as we do on a typical Thursday. We're a fairly small site compared to most on this group, I'm sure, but we usually have pretty predictable flow of traffic, so outlying numbers raise concern.
So... would un-commenting the cookie_domain line affect the "anonymous users" number in admin menu and/or Google Analytics? And, more important, is there anything in the Pressflow/Mercury/Pantheon stack that would clash with the "cookie_domain" thing?
I feel like this question reveals a basic lack of knowledge on my part, but I have all this complex stuff going on the site and am constantly trying to get a better grasp on what it all does. Many thanks for your help!

Comments
honesty is good!
I'll be honest too: groups.drupal.org seems to suffer from the same problem. The traffic to *.drupal.org follows a very predictable weekly sine-wave peaking on wednesday and tapering off on the weekends. But groups.drupal.org has not looked like that for a while. At some point we did change our $base_url and $cookie_domain variables, though I don't know for sure that they are correlated.
knaddison blog | Morris Animal Foundation
Google analytics is usually
Google analytics is usually pretty accurate. Make sure you didn't do something that completely broke your site for a family of web browsers that you don't normally use.
--
Dave Hansen-Lange
Director of Technical Strategy, Advomatic.com
Pronouns: he/him/his
Pressflow & admin menu user count
Admin menu uses the session table for its counting. As you know pressflow doesn't start sessions for anonymous users. Boost stat counter doesn't either if you where wondering.
<?php/**
* Implementation of hook_translated_menu_link_alter().
*
* Here is where we make changes to links that need dynamic information such
* as the current page path or the number of users.
*/
function admin_menu_translated_menu_link_alter(&$item, $map) {
...
if ($item['title'] == 'icon_users') {
// Add count of active anonymous/authenticated users.
// @see user_block(), user.module
$interval = time() - variable_get('user_block_seconds_online', 900);
$count_anon = sess_count($interval);
$count_auth = db_result(db_query("SELECT COUNT(DISTINCT uid) FROM {sessions} WHERE uid > 0 AND timestamp >= %d", $interval));
...
?>
http://api.drupal.org/api/drupal/includes--session.inc/function/sess_cou...
Thanks, all. I guess this was
Thanks, all. I guess this was a false alarm, but this is good stuff to know nonetheless. Site works in all the major browsers, Analytics shows our typical ratio of IE/FF/Safari/other, etc. I guess our content just isn't very interesting this week :) The cookie_sessions thing must just be coincidental.
Thanks,
Sean
Sean Fitzpatrick
Proof Studio
@sffitzpatrick