Although Google claims it has something of a Wal-Mart effect, in that as the economy tightens, users look to spend more wisely and so increase their use of search, the effect seems to have spread to its competitors, Yahoo and Microsoft.

According to monthly numbers published by comScore, Google's share of the Web search market in June went down 0.3% to 61.5%, while Yahoo gained 0.3% to hold a 20.9% share, and Microsoft jumped 0.7%, for a 9.2% share.

The numbers, while representing just a small snapshot overall, don't bode very well for Google, especially since 98% of its revenues still come from search. And with the Yahoo-Microsoft brouhaha simmering down now that Yahoo has come to an agreement with disgruntled investor Carl Icahn, the competition may start to heat up even more. Looks like it's almost time for Google's enterprise-focused businesses (Google Apps, etc.) to step up to the revenue-generating plate.