I use Google search less and less, but still from time to time, and I have indeed noticed a raise in the number of questionable links. It kind of looks like Google is now favoring quantity to quality. Sure the first top links from any search are usually relevant, but then you can have a very long list of really crap links, whereas Google typically used to shorten the list before. Most of the crap comes from sites that "spoof" content in some way, managing to return different information to Google indexing servers than what they serve to a regular web browser. You'd think that Google knows how to avoid this kind of trap by now, it's almost a basic requirement for any search engine...
Although I have absolutely no proof of that, I wonder if this is related to the same kind of "strategic" shift as what they did with Youtube (which wouldn't be all that surprising), now favoring more "diversity" to search results (/ suggestions), thus letting many links slip through (even though of course not at the top ranks), whereas they would just have rejected them in the past.