It would appear that Microsoft has bought Multimap as seen in the Search Engine Land article below:
Microsoft Acquires UK-Based MultiMap Mapping Provider
It would appear that Microsoft is sticking to it's promise of having 40% of the online ad share by 2012. Microsoft intends to intergrate both services into Virtual Earth and Multimap.
Multimap is a long established online maps service which was going way before Google, Yahoo and MSN offered their service.
I have not used Multimap for some time, but it looks like they have changed their interface too. Virtual Earth has some really cool features, but it is far too clunky and slow. It also has problems loading in certain browsers and requiring numerous Active X requests/plug-ins.