This afternoon we attended the "Windows Phone developers day" at Mobile World Congress, during which an extensive Q&A was held that involved various heads of the Windows Phone development team, including Larry Liberman, Bryan Agnetta, Joe Marini, Rob Cameron and Brandon Watson.
A question that Microsoft is commonly asked involves the TCP-socket layer support and whether or not Windows Phone will make it accessible for developers. Socket-layers are critically needed for such services as VOIP aka Skype, Viber, etc. We now know that multitasking is coming to Windows Phone 7 with 'Mango' but now we have a very strong hint that socket-support, in some way, may be coming as well. Those two features are necessary for VOIP. [For a complete background, see J2i.net for relevant points]
Watson does the talking here but dare we say, if you read between the lines you get the feeling that (1) MIX11 will be huge for developers in terms of new features (that are coming with 'Mango') and that (2) Socket-support is a strong contender for a new feature, allowing developers to finally expand beyond simple web-based software. One thing is clear is that Microsoft does not want to disappoint consumers or developers and they are working hard to roll out new features for both, as quickly as possible.