I've just had the following email from the Windows Live Team:
Dear Windows Live Customer,
Thanks for connecting your favorite online services with Windows Live. We are contacting you because you've connected MySpace to Windows Live, and this service is about to change.
Starting in the next several weeks, we will no longer automatically import MySpace activities and contacts into Windows Live. This means that we won't share your MySpace activities with your Windows Live Messenger contacts anymore, and we won't import your MySpace friends activities or updated contact info into Windows Live Messenger or Hotmail anymore.
We remain focused on making Hotmail, Messenger and your Windows PC the best that they can be. Note that this change has no impact on your ability to connect Windows Live to other social networks such as Facebook and LinkedIn.
The Windows Live Team
...so it looks like MySpace is now a well and truly dead social network!