Quote from: Little Mouse on Today at 04:17:46 AM

I can't see any username with davidonpda on bitcointalk. Maybe they have changed their username.

Changing the username will still link the previous posts to the new name since the "User ID" (u=0000000) wont change.

Probably a deleted account and the user's posts were turned into guest posts.
This is probably the explanation on the Anonymous "edited by davidonpda" post: https://bitcointalk.org/index.php?topic=67541.msg789906#msg789906
The user requested to change his posts to appear to be posted by an 'Anonymous' guest, and deleted the account as well. (the OP of that thread didn't, just 'delete account')