It appears that recently Google has been testing a new AdWords placement at he bottom of search engine results pages. Some search engine users have spotted this testing and in the below example there where four AdWords at the bottom of the search results.
The search engine giant is constantly testing new ad placements and formats in an effort to improve its response to certain search criteria. These test are usually shown to a small demographic to begin with and successful ones are eventually rolled out to the general public. If you spot any of these tests please keep us posted.