I'm not a sysadmin, but I'll take a stab at these based on what I know from doing work on page histories. Not that I know of, but there is probably a weak correlation. Circumstances that can affect this include: The user and/or user talk page was created a while after the user's first edit/account creation. In my case, I created my user page three months after creating an account, and my user talk page was created one month after my account creation. The user or user talk page was deleted at some point, but not to make way for a page move (see below). When a page is deleted, it loses its old page ID, and when it is undeleted or re-created, it gets a new page ID as if it is a brand new page. This can be demonstrated on-wiki by using the whatlinkshere function, which orders pages by page ID. For example, in Special:Whatlinkshere/Fleishhacker Pool, one would expect the swimming pool article to be listed first, as it was created in March 2002. However it is listed at the end because it has been deleted and restored several times. Yes, assuming the user and talk pages were moved with the page move function, which preserves the page ID, even when a deletion is required to make way for a move. For an on-wiki demonstration, see Special:Whatlinkshere/Biscayne Aquifer and note that Miami is listed near the top even though it was deleted to make way for page moves from Miami, Florida several times. You might also be interested in the effects of username changes before the advent of the user rename tool for bureaucrats. The user's settings and watchlist were transferred, but their edits were not. For example, see this diff - the second edit of that diff is ClockworkSoul's first recorded edit. That depends on page moves. When my username was Pianoman87, I received messages addressed to User talk:Pianoman87, but they are now in the page history of my current user talk page. Currently, the user with the most recent user ID will probably get a message posted to their user talk page, but I'm not completely certain of this. I just tested this on my old username, and I received a new messages bar when I logged in to that account. Also see the contributions of that account, and note the earlier contribs, which were edits that were deleted when I was Pianoman87 but undeleted when my username was changed. User:0 seems to have been used as a placeholder username in the phase II software, so that's why it would have multiple IDs. Hope this helps. Graham87 06:22, 11 January 2009 (UTC) BTW, renaming a user now changes the username in all deleted edits by that user, so the above problem with early contributions attached to my old username, Pianoman87, isn't an issue for users who were renamed since late July 2007 (I changed my username in March 2006). Graham87 07:00, 11 January 2009 (UTC) I'm not a sysadmin, but I'll take a stab at these based on what I know from doing work on page histories. Not that I know of, but there is probably a weak correlation. Circumstances that can affect this include: The user and/or user talk page was created a while after the user's first edit/account creation. In my case, I created my user page three months after creating an account, and my user talk page was created one month after my account creation. The user or user talk page was deleted at some point, but not to make way for a page move (see below). When a page is deleted, it loses its old page ID, and when it is undeleted or re-created, it gets a new page ID as if it is a brand new page. This can be demonstrated on-wiki by using the whatlinkshere function, which orders pages by page ID. For example, in Special:Whatlinkshere/Fleishhacker Pool, one would expect the swimming pool article to be listed first, as it was created in March 2002. However it is listed at the end because it has been deleted and restored several times. Yes, assuming the user and talk pages were moved with the page move function, which preserves the page ID, even when a deletion is required to make way for a move. For an on-wiki demonstration, see Special:Whatlinkshere/Biscayne Aquifer and note that Miami is listed near the top even though it was deleted to make way for page moves from Miami, Florida several times. You might also be interested in the effects of username changes before the advent of the user rename tool for bureaucrats. The user's settings and watchlist were transferred, but their edits were not. For example, see this diff - the second edit of that diff is ClockworkSoul's first recorded edit. That depends on page moves. When my username was Pianoman87, I received messages addressed to User talk:Pianoman87, but they are now in the page history of my current user talk page. Currently, the user with the most recent user ID will probably get a message posted to their user talk page, but I'm not completely certain of this. I just tested this on my old username, and I received a new messages bar when I logged in to that account. Also see the contributions of that account, and note the earlier contribs, which were edits that were deleted when I was Pianoman87 but undeleted when my username was changed. User:0 seems to have been used as a placeholder username in the phase II software, so that's why it would have multiple IDs. Hope this helps. Graham87 06:22, 11 January 2009 (UTC) BTW, renaming a user now changes the username in all deleted edits by that user, so the above problem with early contributions attached to my old username, Pianoman87, isn't an issue for users who were renamed since late July 2007 (I changed my username in March 2006). Graham87 07:00, 11 January 2009 (UTC) I'm not a sysadmin, but I'll take a stab at these based on what I know from doing work on page histories. Not that I know of, but there is probably a weak correlation. Circumstances that can affect this include: The user and/or user talk page was created a while after the user's first edit/account creation. In my case, I created my user page three months after creating an account, and my user talk page was created one month after my account creation. The user or user talk page was deleted at some point, but not to make way for a page move (see below). When a page is deleted, it loses its old page ID, and when it is undeleted or re-created, it gets a new page ID as if it is a brand new page. This can be demonstrated on-wiki by using the whatlinkshere function, which orders pages by page ID. For example, in Special:Whatlinkshere/Fleishhacker Pool, one would expect the swimming pool article to be listed first, as it was created in March 2002. However it is listed at the end because it has been deleted and restored several times. Yes, assuming the user and talk pages were moved with the page move function, which preserves the page ID, even when a deletion is required to make way for a move. For an on-wiki demonstration, see Special:Whatlinkshere/Biscayne Aquifer and note that Miami is listed near the top even though it was deleted to make way for page moves from Miami, Florida several times. You might also be interested in the effects of username changes before the advent of the user rename tool for bureaucrats. The user's settings and watchlist were transferred, but their edits were not. For example, see this diff - the second edit of that diff is ClockworkSoul's first recorded edit. That depends on page moves. When my username was Pianoman87, I received messages addressed to User talk:Pianoman87, but they are now in the page history of my current user talk page. Currently, the user with the most recent user ID will probably get a message posted to their user talk page, but I'm not completely certain of this. I just tested this on my old username, and I received a new messages bar when I logged in to that account. Also see the contributions of that account, and note the earlier contribs, which were edits that were deleted when I was Pianoman87 but undeleted when my username was changed. User:0 seems to have been used as a placeholder username in the phase II software, so that's why it would have multiple IDs. Hope this helps. Graham87 06:22, 11 January 2009 (UTC) BTW, renaming a user now changes the username in all deleted edits by that user, so the above problem with early contributions attached to my old username, Pianoman87, isn't an issue for users who were renamed since late July 2007 (I changed my username in March 2006). Graham87 07:00, 11 January 2009 (UTC) I'm not a sysadmin, but I'll take a stab at these based on what I know from doing work on page histories. Not that I know of, but there is probably a weak correlation. Circumstances that can affect this include: The user and/or user talk page was created a while after the user's first edit/account creation. In my case, I created my user page three months after creating an account, and my user talk page was created one month after my account creation. The user or user talk page was deleted at some point, but not to make way for a page move (see below). When a page is deleted, it loses its old page ID, and when it is undeleted or re-created, it gets a new page ID as if it is a brand new page. This can be demonstrated on-wiki by using the whatlinkshere function, which orders pages by page ID. For example, in Special:Whatlinkshere/Fleishhacker Pool, one would expect the swimming pool article to be listed first, as it was created in March 2002. However it is listed at the end because it has been deleted and restored several times. Yes, assuming the user and talk pages were moved with the page move function, which preserves the page ID, even when a deletion is required to make way for a move. For an on-wiki demonstration, see Special:Whatlinkshere/Biscayne Aquifer and note that Miami is listed near the top even though it was deleted to make way for page moves from Miami, Florida several times. You might also be interested in the effects of username changes before the advent of the user rename tool for bureaucrats. The user's settings and watchlist were transferred, but their edits were not. For example, see this diff - the second edit of that diff is ClockworkSoul's first recorded edit. That depends on page moves. When my username was Pianoman87, I received messages addressed to User talk:Pianoman87, but they are now in the page history of my current user talk page. Currently, the user with the most recent user ID will probably get a message posted to their user talk page, but I'm not completely certain of this. I just tested this on my old username, and I received a new messages bar when I logged in to that account. Also see the contributions of that account, and note the earlier contribs, which were edits that were deleted when I was Pianoman87 but undeleted when my username was changed. User:0 seems to have been used as a placeholder username in the phase II software, so that's why it would have multiple IDs. Hope this helps. Graham87 06:22, 11 January 2009 (UTC) BTW, renaming a user now changes the username in all deleted edits by that user, so the above problem with early contributions attached to my old username, Pianoman87, isn't an issue for users who were renamed since late July 2007 (I changed my username in March 2006). Graham87 07:00, 11 January 2009 (UTC)