Despite many well-publicized failures of would-be Google killers, fresh combatants keep coming. Here are some of the most prominent:
BINGMicrosoft is spending $100 million on marketing its recently relaunched search engine. Bing's market share rose from 8% to 9.5% in August, while Google's fell from 71.4% to 70.2%.
TWITTERThe microblogging startup, with a recent funding round that valued it at $1 billion, now handles at least 37 million searches a month, only a few months after introducing a search box. But that's still tiny compared with Google's 76 billion a month.
ONERIOTThe Boulder (Colo.) startup is among the leaders of a large pack of real-time search engines. OneRiot searches current news and posts on Twitter, Digg, and other social sharing services.
WOLFRAM ALPHAFounded by Stephen Wolfram, creator of the Mathematica software program, this "computational knowledge engine" aims to provide definitive answers to factual queries.
AARDVARKOne of several answer services, including ChaCha, Mahalo, and Yahoo Answers, that marshal friends and topic experts to provide fast responses to queries.