Bing is partnering with Encyclopaedia Britannica to bring richer content to its search results. The partnership is the first of its kind for Britannica, which recently became a web-only entity after 244 years of printing its encyclopedias. Although it's easy to look at this as a knee-jerk reaction to Google's Knowledge Graph, the two services are quite different — Microsoft already has a system for semantic search. Whereas the Knowledge Graph provides encyclopedic stubs outside of the regular search results, Microsoft is simply providing more detailed search results when Britannica appears naturally within search results.
Unfortunately, due to Wikipedia's popularity, Britannica results don't often appear on the front page of searches, and it remains to be seen if Microsoft will artificially place Britannica results higher within search results. You can try out the new feature now on Bing — here's a search term to get you started.