In the next few days, we’re launching an important algorithm change targeted at webspam. The change will decrease rankings for sites that we believe are violating Google’s existing quality guidelines.
The change will go live for all languages at the same time. For context, the initial Panda change affected about 12% of queries to a significant degree; this algorithm affects about 3.1% of queries in English to a degree that a regular user might notice.
Here’s an example of a site with unusual linking patterns that is also affected by this change. Notice that if you try to read the text aloud you’ll discover that the outgoing links are completely unrelated to the actual content, and in fact the page text has been “spun” beyond recognition:
Yeah. Go do a search for one of your keywords. You think the results were bad before, it's pretty crazy at the moment. I've got Wikipedia pages that aren't even related, showing up in the top 10. A twitter page of some random company. And a page from some independent search engine from 1997 It's going to take a while for this one to get sorted out.
Looks like they are detecting spun content (on other sites with your link in it) and penalizing for it.
I've got a site that I haven't optimized / or built links to / or added content to since 2006 that just popped up on the 1st page for some pretty competitive keywords.
Go figure.