The latest figures for share of the search market should convince Microsoft it's time to give up trying to buy Yahoo. Buying Yahoo won't help in the fight against Google -- it'll only weigh down Microsoft with a sinking company.

The firm Hitwise just released a market study that shows that Google's share of the search market is at an all-time high, while Microsoft's and Yahoo's continues to decline. For March, Google had 67.25 per cent of all Internet searches, compared to 20.29 per cent for Yahoo, and 6.65 per cent for search.msn.com.

Google's share is up from 66.44 per cent in February. Yahoo's is down from 20.59 per cent in February. And Microsoft's is down from 20.59 per cent in February.

Even worse is looking at figures from a year ago. In March of 2007, Google had a 64.13 per cent share, while Yahoo had 21.26 per cent, and Microsoft 9.01 per cent. So in one year, Google went up more than 3 per cent, while Microsoft and Yahoo combined dropped a little more than 3 per cent.

Buying a company with shrinking market share can't help Microsoft succeed online. As I've written before, buying Yahoo will divert money, resources, and attention from Microsoft. At a time when Vista is having a hard time gaining a footheld, and the stakes for Windows 7 are so high, the last thing Microsoft can afford is what in essence amounts to a hostile takeover of another company.

Instead, it should focus on Windows, and on figuring out how to make an online version of Office as a way to succeed online.