Wikipedia has a ton of traffic. The site accounts for about 1 in every 200 U.S. internet visits. With that volume of traffic, it's worth asking where Wikipedia users go after they're done reading entries in the peer-edited encyclopedia.

According to Hitwise, 10 percent of Wikipedia's users went straight to Google for an additional search. That's a sizeable number both in terms of total volume and with respect to behavior, since 51 percent of Wikipedia's traffic comes from Google, meaning that many users bounce between searching some version of answers and back again to searching.

If a second search isn't a consideration for Wikipedia users, MySpace appears to be the big winner, taking in 3 percent of Wikipedia's exit traffic. IMDB.com, YouTube and Yahoo round out the top five downstream sites.

While Wikipedia doesn't monetize its site, the exit traffic underscores a larger interest in the reference space. While Wikipedia dominates reference, most major players have looked to build their own reference sites, with varying degrees of success. Most recently, Google said it planned to take a chunk out of reference by launching Knol, a platform designed to match Wikipedia-style scope with encyclopedic credentials with respect to accuracy.