Google and start-up Blekko are competing on features to block increasingly sophisticated spam results
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Blekko Antispam Search Engine Could Teach Google A Thing Or Two
Google should learn from Blekko, a search engine startup that helps users avoid spam with slashtags, said Clint Boulton
Blekko Custom Search Challenges Google
Blekko, the latest rival to Google, uses crowd-sourced search results to weed out spam and irrelevant results