The act of aimlessly clicking through links in an online wiki, such as Wikipedia, often driven by boredom and wanton curiosity. This is facilitated by the fact that most wiki's are crosslinked everywhere, so you may very well look up "Potato" and eventually wind up in "Vaginal Suppository".
Wikidrift is the process in which you proceed through different topics only by using the links available on that certain page.
It usually occurs when the other topic is of more interest to yourself than the one you are currently viewing, having a higher occurance when one is studying.