Yahoo blocked third party instant messenger applications from using their network yet again, something that all three of the locked-in networks seem to do with monotonous regularity and futility.
As Jeremy Zawodny (a Yahoo employee) pointed out this is a fundamentally pointless exercise, with significant echos of the major failings of DRM, in that the blockage gets worked around quickly and the temporary inconvience also actively encourages people to leave Yahoo as their IM of choice. In fact, Trillian users can already get around the block by getting a new patched version of the popular client. Neil Turner reports that the Gaim client and Jabber gateways were also not significantly inconvenienced by the blocking. It makes you wonder why Yahoo bothered with the exercise.