Wikipedia Advertising Shows Up on Google

Links to Wikipedia articles have started to show up on Google Adwords. For example, this search for crowdsourcing pulls up a Wikipedia ad. (Note third link in the screen grab below.) It's unclear if these ads were placed by the WIkimedia Foundation or if parties interested in directing searchers to these articles are doing so.

Regardless, the trend is fascinating. Although it's risky for a brand to direct people to a Wikipedia article purposefuly, it's certainly welcome from a searcher's POV. That said, Wikipedia articles are not exactly difficult to find. The entry on crowdsourcing is number four in the natural search results. So, with that, I am not sure what Wikimiedia or a third party is gaining here by advertising.