http://business.timesonline.co.uk/tol/business/industry_sectors/technology/article6837577.ece

<<Microsoft’s Bing search engine is emerging as a challenger to the dominance of Google after capturing a near-11 per cent share of the market in little more than three months.

The latest statistics from Nielsen, the research firm, show that Bing, which went live in June, is now the fastest-growing internet search engine in the United States. Its market share leapt to 10.7 per cent in August, from 9 per cent in July — a rise of more than 22 per cent.>>

[Edited to include snippet, which makes it easier to get an idea of the article before clicking through (it also helps should the original article ever disappear or become reg-only). -Philipp]

According to StatCounter (http://gs.statcounter.com/#search_engine-US-monthly-200905-200909) Bing's share declined in September.

Franta, isn't Nielsen more respected though?

I definitely think Bing is a formidable competitor (and use it quite often), but isn't it too early to call it a challenge to Google?

...Especially considering the fact that Google's total marketshare didn't decline...meaning Bing's gain is at Yahoo's expense.

And for those arguing that Google's growth has 'stalled' or anything along those lines, remember law of diminishing returns ;)

Philipp: Thanks for editing and adding the snippet. My contributions are done with mobile browser during last weeks and copy/paste is not so easy with those browsers. I have added a text later if possible.