Speaking frainkly I find (on a daily basis) too many abused VPNs to think TOR won't bring tons of abuses. Some months ago (I cannot remember when) TORblock stopped working. Having a look at what did happen at time would be an interesting path. In my perception it did bring to an increase in abuse (spam/trolling/vandalism).
Might you have been talking about Bug #30716? [1] It happened in September of 2011. In May of 2012 the bug was re-opened and it hasn't yet been closed.
Thank you, Derric Atzrott