Keyword abuse is rampant everywhere. Some sellers on craigslist can't be bothered to change their templates so all kinds of irrelevant stuff shows up. Ditto YouTube and any user-driven site that allows users to determine keywords or folksonomy.
In some cases -- especially blogs -- pre-cooked templates are stuffed with keyword spam by the template creators. The actual blog owners or template users aren't even aware they're promoting keyword spam.
Fortunately Google does a pretty good job of identifying the worst offenders and can help screen them out. I use Google searches, specifying the site I want to search, when a site's own search tools present too many irrelevant hits.