Looks like all of the links in your profile were marked with a "nofollow" attribute, which in turn told our engine to stop rendering them as links.
This is _probably_ a side-effect of your other site profiles having lower reputation and MathOverflow joining the SE network. ("nofollow"ing links from new-ish accounts is in place to prevent the less scrupulous folks from creating profiles and using them to set up a link farm.)
I edited your profile to remove the "nofollow" attributes and copied your profile to your other sites as well. All the links should be working as expected now. Please let us know if this happens again for some reason and we'll dig into it further.