"We found that many users were extremely loyal to the Hotmail brand and perceived the beta as an upgrade to Hotmail," said Richard Sim, a Microsoft senior product manager, on the service's blog. "In fact, while [users] loved the improvements in the beta, some were a bit confused by [the] name change."

Rather than dubbing the revamped service Windows Live Mail, Microsoft is calling it Windows Live Hotmail, said Sim.

Hotmail, which Microsoft acquired in 1998, has been in redevelopment since mid-2005 but remains in beta testing except in the Netherlands, where it went final in November. The most recent revision, pegged as M9, rolled out on Wednesday.

Originally, Windows Live Mail was to be a top-to-bottom redesign that would bring the service in line with the interface of Microsoft's Outlook e-mail client -- and Windows Vista's Windows Mail entry-level client. But Microsoft backtracked so it could reinsert a "classic" look.

Sim said the name change would migrate to users in the next few weeks.