Today, Blekko opens up to the public. They've been in private beta since July and are finally opening the doors to the masses. Of course, just because Blekko is a search engine, comparisons are immediately being drawn with Google. In reality, it's like comparing apples to oranges.
blekko is a better way to search the web by using slashtags. slashtags search only the sites you want and cut out the spam sites. use friends, experts, community or your own slashtags to slash in what you want and slash out what you don't.
The primary problem that Blekko addresses is the amount of spam and irrelevant results you get when searching on a specific topic. SEO is somewhat complicated, but it's not rocket science to get a relatively useless site ranked in Google. Many topics you might want to search for are dead from the start because of this (anything health/fitness, for example). Blekko not only cuts through clutter, but also allows you to do things with search that just aren't possible with keywords.
Blekko accomplishes all of this by allowing users to create vertical search engines (search engines focused on a specific topic or group of sites). Google is a horizontal search engine, pulling results from sites across the web that have nothing to do with each other. Blekko's more focused and crowd-sourced approach is what has many interested.
Will it challenge Google? I doubt it. I think they are tools for different jobs. While Blekko allows you to go through the web with a fine-toothed comb, sometimes you just need a pick with a fist on the end.
Five use cases where slashtags shine
Verticals with just YOUR favorite sites:u2 /music, iphone reviews /tech, wine /buy, 2010 season /steelers, American Idol /tv
Search you can't do with keywords:global warming /conservative, ufos /paranormal, congress /humor, Kim Kardashian /gossip
Slash through heavily spammed categories:avoiding swine flu /health, iphone 4 reviews /techblogs, Aruba /travel, low calorie /diet
Access to recent material and web data:Obama /date, Mel Gibson /rank, cnn.com /seo, techcrunch.com /links
Direct access to 3rd party api's:US Open /youtube, Twilight /twitter, Moby Dick /amazon, sports car /shop