Is LINQ to SQL deprecated?
For all the "Linq-to-SQL is dead" folks: Scott Guthrie himself clearly mentioned at TechEd Europe that Linq-to-SQL is FULLY SUPPORTED in .NET 4, and Damien Guard posted a blog post on what changes and improvements have been made for Linq-to-SQL in .NET 4.
To quote Mark Twain: "Reports of my death have been greatly exaggerated"......
Last I checked, this very site uses (or used to use) Linq To SQL. Joel Spolsky mentions this in his GoogleTechTalk: http://www.youtube.com/watch?v=NWHfY_lvKIQ.
When speaking of software, "dead" is a figurative modifier (software doesn't die in any literal, biological sense), so this debate can linger on as long as the involved parties refuse to define in any literal sense what it means for "Linq To Die". Or, LTD for short. Hence, as of this moment, the LTD debate has lingered for two years. All because of a little linguistic ambiguity.
Those who say that "L2S is dead" are generally referring to the fact that L2S isn't going to receive too many (if any) new features. Updates to Linq (like the updates mentioned in Damien Guard's post) are likely to be confined to performance, usability, and stability updates. Of course, some developers might actually argue that this is a good thing (probably the same developers who are a wee bit angry about the new dynamic type).
Those who say that "L2S is not dead" are generally referring to the fact that L2S isn't going to be cut altogether from .Net (at least not anytime soon). Think: ADO. It may lose some of its traction amongst practicing developers (and that may be the unspoken desire of those crafty folks at Microsoft), but that doesn't mean that you won't be able to use L2S if you want to. It just means that Microsoft isn't trying to tantalize the masses with it.
When starting a project, I actually think it's great that I have a choice between EF and L2S. As Bill Wagner points out, there's a time and a place for both.