You probably know Technorati, "zee" search engine of the blogosphere. I discovered today one of its competitor, Blogpulse.
On a similar concept — index everything blogging so you can search within weblogs, or, let's be honest, check how many sites are linking to yours, which always turns into a disappointing experiment — Blogpulse adds an interesting feature, trend searches.
For example, early march keyword "Ozh" has been used in 0.00175% of the blogs ! Amazing ! Yet another disappointing experiment :)
Trend searches can also make a fine spam analysis tool : let's compare how three agressive spammers are doing these months !
You could also study trends for high click ratio keywords in order to optimize your traffic and your AdSense incomes, but that would be much more boring and no fun at all.
