There was a story in the news recently of a Harvard student who used Tor to send a bomb threat to Harvard in order to cancel classes so he wouldn't have to take a test. He was apprehended within a day, which puts into question the anonymity of Tor.
From my understanding (please correct me if I'm wrong) Tor has a weakness in that if someone can monitor data going into the relays and going out of the exit nodes then they can defeat the anonymity of tor by correlating the size and number of packets being sent to relays and comparing those that the packets leaving the exit nodes.
Are there any projects in Tor being worked in to combat data correlation? For instance, relays the send/recv constant data rates continuously - capping data rates and padding partial or non-packets with random data to maintain the data rates