Wikipedia is such a huge resource, and has so many people both reading it and citing it, that I was glad to hear about Wikirank. Wikirank, available at http://wikirank.com, allows you to search for topics and get a chart of how many views their Wikipedia pages have gotten. Furthermore, you can compare different pages against each other to see which is more popular.
You can see an dramatic example of a Wikirank view chart when looking at Natasha Richardson’s page. (Note that Wikirank’s search engine appears to be case sensitive; searching for “Natasha richardson”, for example, gets no results.) Readership is steady with an astounding spike on March 19, the day after her unfortunate death. Other charts I looked at tended to be steady or with much lower spikes (Take Stan Lee for another example.)
You can also do comparative searches. Start with the Wikirank page on Jon Stewart (which also has a short spike.) Once you have that page up you can click on the “Compare This Topic” button, and Wikirank will invite you to search for another topic. In this case I searched for Jim Cramer. You’ll get a chart that shows the readership of both pages. In this case Jon Stewart and Jim Cramer both have a spike on the same day (I suppose for the famous Daily Show interview) but Cramer’s spike is higher. You can compare up to four topics at a time. (I tried to add CNBC to this search and was interested to see that it had no spike at all — just a steady, comparatively low readership.)
I would love to have RSS for trending data, or even an API (which the site says is coming soon.) Excellent site if you’re at all interested in Wikipedia.