My good friend Ralf has pointed me at a brief mention of F# on the monthly TIOBE index, a programming language popularity measure based on a simple count of hits returned by a web search. It seems F# has begun registering a few more hits of late.
There are a couple of corrections to make to the TIOBE description of F#. F# is not an official Microsoft language: it is more accurate to call it a "research language", created by the F# team at MSR Cambridge. Of course, it works well with Microsoft and other CLI-based technologies and aims to complement the existing official range of Microsoft languages by being the best functional language on the .NET platform. It also proves the potential for succinct, high-performance, scalable and interoperable .NET scripting based on mixed functional/imperative/OO programming.
Additionally, there's been no recent shift to an official "beta" release, though we have made some important releases of F# of late (the latest being 184.108.40.206). Each release of F# combines the solid foundation language with more experimental features (the foundation language is very much inspired by that of core OCaml, though with very considerable .NET-related extensions) . This approach to language development is normal for languages shipped by research organisations, combining both reliability and innovation.
Other than that, thanks to the TIOBE guys for the mention, and thanks to Ralf for the nice quote :-)