I don't even need to click on this link. Let me just guess:
Many years ago Obama had a cocktail with a college professor who, it turns out, is a raving anti-Semite and terrorist sympathizer. There was no reason for Obama to have known this beforehand, and even if he did, no reason to turn down the cocktail, because a) he wasn't running for president at the time and b) briefly crossing paths with someone does not constitute an endorsement of their worldview.
It is laughable how you right-wingers get so worked up over what Obama *might* turn out to be, while remaining willfully ignorant of what the Republican-controlled government *actually is* and has been for the last several years.
Want to see "linked to a terrorist," literally? Here you go:
Slate Magazine