As Doug McIntyre wrote yesterday, Google Inc. (NASDAQ: GOOG) increased its web search popularity in the U.S. pretty dramatically in March. While Google continues to make headway with web search volume (and making quite a bit of money within that market), Yahoo! Inc. (NASDAQ: YHOO) and Microsoft Corp. (NASDAQ: MSFT) have (so far) shown that they are not making any solid gains on Google. A distant player, Ask.com, owned by Barry Diller's InterActive Corp. (NASDAQ: IACI), maintains about 4% of the web search marketplace.

Will any other search engine ever seriously challenge Google? For the near future, probably not. Yahoo! is in the business of building relationships with paying customers (Terry Semel's vision, I think) and Microsoft has a pretty diversified product and revenue stream, although Windows and Office are the main cash cows. Do they need to complete with Google better? They should be (although not a die-hard requirement), and both companies are probably tired of Google riding off into the sunset with all that cash. Microsoft's constant claim that its Live.com search engine is central to its strategy may be fine, but actions speak louder than words. Where are the actions?

Google has an enormous first-mover advantage here. Not because it was first with a search engine index, but because it was first with a search engine with text ads that customers not only found unobtrusive, but helpful in many cases. That alone is why Google is where it is, and why the other companies can't keep up.