Although I have a handful of blogs, most of my traffic is from organic searches. It is a wonderful feeling when people look up for information on certain keywords and land in your blog. This is the reason I like the check my traffic stats to see where people come from. This is also the way I managed to discover quite a few sites.
It is surprising that there are many search engines around even though my primary search engine is Google and if Google fails me, I may use Yahoo and Windows Live but judging from people who found my blog, they use other search engines and blog search sites as well. My default blog search, by the way, is Google Blog Search.
Anyway, out of curiosity, I did a search on the internet to see how many search engines there are and came upon this page on Wikipedia. While I know that Wikipedia is not 100% accurate, the list of search engines on the page is pretty exhaustive and there are some that I never even herd before.
If you are interested in checking what search engines there are, check out the page in Wikipedia.