People working at traffic measurement companies are probably less than happy right now.  With the introduction of Google Trends for Websites, a certain search giant is invading their niche.

Like most of Google’s tools, Google Trends for Websites is free.  Like some of them, it’s interesting.  Sign in, type a site’s address (or more than one address, if you want), and you’ll get to see a graph representing its daily unique visitor count over a period of time.  Sites those people "also visited" and "also searched for" are listed, along with proportional traffic bars, as well.

This appears to present all sorts of opportunities for competitor research, ally-making, and general site-to-site comparisons.  What keeps the tool from being "interesting" as opposed to "remarkable," then (and keeps us from thinking about bankruptcy in connection with Alexa, Compete, and the like) is that it remains to be seen how accurate Google’s data is.

On the Webmaster Central Blog, R.J. Pittman writes, "Keep in mind that Trends for Websites is a Google Labs product and that we are experimenting with ways to improve the quality of the data.  Because data is estimated and aggregated over a variety of sources, it may not match the other data sources you rely on for web traffic information."

Still, we feel fairly sure that a lot of people have just found a new way to spend the impending weekend.