Last week I put up a post celebrating the Vatican's being on Twitter. It turns out that this was an imposter (Te Deum has the details) so I have deleted the post. It seems that the incident has prompted at least one person at the Holy See to reflect “It wasn’t us — but it should have been us.”
Apologies for the misinformation. I have removed the offending post.
There are at least three other "Vatican" Twitter accounts so you can take them with a pinch of salt as well.