Blekko, a search engine that I previously posted on, has been holding strongly to their word about the excess of content farms and spam, and have been tracking the growth rate of spam with CEO Rick Skrenta's "Spam Clock" creation.
At the beginning of 2011, Blekko began tracking (via the Spam Clock) how many pages had been created that were essentially deemed spam. Today, the clock has ranked up over 250 million spam pages that have been created since January 1, 2011. The website also states that about 1 million spam pages are created every hour.
The problem with spam websites, for those who are unaware, are that they dilute search engine results and make it difficult for searchers to locate legitimate websites containing the information/products that they are looking for. In Blekko's words, they steal clicks and also increase click fraud. In essence, they are counterproductive to the whole scheme of search.
For more on the Spam Clock and the impact of spam on search engines, you can check out Search Engine Land's take on it all.