More and more, LINQ to SQL is being seen as a temporary solution. With the impending release of ADO.NET Entity Framework, a lot of people are worried that development on LINQ to SQL will fall by the wayside. With Microsoft's long history of developing and discarding database access technologies, these concerns are not without merit.
Further compounding the issue is that LINQ to SQL has been transferred to the SQL Data Programmability team, the very same group working on ADO.NET Entity Framework. With their own project filling a similar role, it is hard to see them wanting to devote a lot of time to the adopted project.
So this raises the question, "Should LINQ to SQL Go Open Source?" Leon Bambrick asks that question and provides some analysis. One of the biggest concerns he raises is the liability issue, wherein Microsoft may be reluctant to ship something with the framework that has had external contributions. On the other hand, it might be what's needed to push through community-driven features such as mockability and multiple providers.