Two years ago America Online decided to block outside access to its instant messaging system, in a heavyhanded tactic that made their boo-hoo complaints about Microsoft look very hollow.

It may have backfired. A new study shows Microsoft Messenger has taken the lead in worldwide and US usage. And MS Messenger is even more deeply embedded in upcoming Microsoft releases of operating systems and net services.

The article has a good description of Microsoft’s tactics, by the way, which strike me as eminently fair: “Target the software that potentially threatens the Windows franchise, create your own version, tie it closely to Windows, push your product as a standard, solicit developers and vendors to build and sell it, and then watch market share tilt in your favor.”