Here is the schedule of the planned tests:
Phase 1 starts on Tuesday 29th of March at 1 PM (PST) and ends on Wednesday 30th of March at 1 PM (PST). During this period all clickable links will be disabled (You are probably not able to send messages containing them). Winks and DDPs will be enabled.
Phase 2 starts on Wednesday 30th of March at 1 PM (PST) and ends on Thursday 31st of March at 1 PM (PST). During this period you will not be able to send or receive any Winks or DDPs. Links will be enabled.
Again, only users of build 732 are affected! If you find an exploit with the security measures (try to find a way to still get links working, send Winks, etc) please report them here or on a forum like
http://forum.mess.be so the official testers may bug them on Beta Place.
Edit: Taken from msnblog.stuffplug.com