@Maddus Mattus:Thanks for letting us know about the links, we are getting that fixed, hopefully resolved during the day tomorrow.
As for turning it on by default, that wasn't the original plan, but we decided that very few people would notice the option and enable it if we left it off to start with. And since we are a Microsoft site, and the contents of your MSDN profile are all publically visible across a set of other Microsoft sites, that linking this together for everyone by default would be nothing but a positive for our users. Having said that, if someone doesn't want this, it is very easy to turn off without even having to go to your profile page... the toggle button is right in the hover box.
Let me know what you think about the feature and this decision, either here or via email, thanks