Technically speaking I think there was more importing going on when we first opened to the public in May of 2009, although we haven't keep detailed traffic logs like that for eight years so I can't say for sure. You can sort of map out a timeline of bad decisions by looking at the detailed account creation history (newbyday), although those numbers can be a bit misleading: one new user creating an account and then importing their journal from LJ can cause dozens or even hundreds of new "accounts" (actually OpenID placeholders) to be created in order to properly attribute comments. So it's not that we had 25,000 individual people sign up yesterday. But it sure has been a lot! (There are more human-readable stats with pretty pictures, but the raw numbers give an interesting historical overview.)