A recent influx of users adopting the names of celebrities prompted re-examination of Wikipedia's username policy, which discourages usernames that are the names of famous people or events.
In response to the proliferation of users like Hilary Duff and Scott Peterson, Zanimum proposed an addition to the policy that "no user may impersonate another living person other than themselves, particularly a person that is worth encyclopedic note". This follows an earlier Arbitration Committee case in which two sockpuppets were blocked because they adopted false names belonging to real people. (Sockpuppets that impersonate other users are also routinely blocked.)
Requests for comment were started last week with respect to two users for impersonating Peterson and Joe Scarborough (the Scarborough imitator was sloppy enough to misspell this U.S. politician's last name and later created a second account with the correct spelling).
In one way or another, these users generally tried to convey the impression that they were the famous—or infamous—person in question (Zanimum said he thought Jerryseinfeld less problematic because he didn't pretend to be Jerry Seinfeld). But besides the sheer improbability of it, a little investigation usually made the impersonation fairly obvious.