Niner since 2010
I've found a previous blog of yours, which described a potential solution in SL3 and presumably .NET 3.5 WCF.
I'm wondering whether it now works out-of-the-box with SL4 and .NET 4, or does it still require the solution in your post I've linked to.
Does the WCF duplex communication with Silverlight work in a web farm and on Azure?
Is it the intention that RIA and WCF Data Services will become one technology in the future? When update support is added, will that leave any unique features of Data Services?