Someone discovered a large chunk of blog.twitter.com was gone, so some screwing around has already happened. The IA is now below Wikipedia for credibility :/
It will be interesting to see if it comes back, or if there is an explanation offered.
If people have been in there for years altering data do they have enough backups to fully detect it?
Do they have mechanisms to verify existing data with backups? Are they even bothering? It would be nice to know - until then I think the IA is interesting, but not trustworthy.
Even a full deletion in one datacentre shouldn't erase an entire chunk like that.