i'm interested in this too.

So far have drawn a blank on this. I did some eye-balling of the top 20 US sites (according to this http://www.alexa.com/topsites) and they mostly seem to use Arial, Arial Bold and Tahoma and Tahoma Bold. But I'm sure this isn't representative of the wider web.

Never figured you for a lister, Si.

I'm not a lister! Background: Some internet-browsing devices don't have enough memory for all the fonts we ship in full OS's so I'm looking to provide a prioritized list based in part in actual usage.

Si, I'm not sure that this is what you need, but Code Style has a pretty complete (and ongoing) survey of Web fonts - in fact, it's the best around. Their recent (April 11, 2009) Full Windows font survey results are fascinating, if not incredible: Franklin Gothic Medium is on 97.62% of surveyed Windows machines? Gill Sans MT is on about half of all surveyed Windows machines?

Thanks, yes I'm familiar with that one. However it doesn't seem to relate to the popularity of fonts specified on Web pages.

Re. Franklin Gothic Medium - that is a core UI font in Windows XP, that stuck around. Gill Sans however most likely got installed with Office.

Cheers, Si