An exercise in idle curiosity, this, spurred by a conversation last week with a VC in New York.

It's clear that there's a highly vocal and highly technical group of people who love all of the technical things you can do with Android phones that you can't do on iOS, consciously reject the iPhone and care deeply about 'openness' and all the things that go with it. However, it's also clear that these people are a minority of actual Android users, given that the typical use levels seen from Android in totality are lower than those from the iPhone (often much lower).

What hasn't been clear, though, is quite how small that community is.

One interesting proxy for geeks who care deeply about 'open', of course, is desktop Linux. There is (obviously) no central source for Linux users, but we can still get a pretty good idea. Ubuntu, which is probably the single most popular flavour, claims 20m daily users. Meanwhile Wiki provides a useful set of stats for devices hitting their servers: it claims that 1.42% of requests in March 2013 came from Linux (excluding Android Linux), of which 0.5% was ubuntu - 35% share. Scaling this up (and treating people who only use desktop Linux occasionally rather than daily as being outside the definition) would imply about 57m users. This is quite close to the Linuxcounter estimate of 66m.

(The global PC base (desktops and laptops, not servers) at the end of March was somewhere in the 1.6-1.7bn range, implying a notional 3.6% share, but that's not really a good comparison, since many of those PCs, both linux and other, will not be online. )

So, the Linux proxy says 60m or so, but can we get a more specific sense of geeks using Android? Another proxy is use of ROMs - custom versions of Android you install yourself. Probably the most popular (outside China) is Cyanogenmod. This reports about 5.4m users, but an unknown number have turned off statistics reporting. Other leading ROMs include AOKP, which passed 1m installs in April, and MIUI, which hit 1m in February. That means there are at least 7m people who've done this (assuming no overlap), and probably rather more - say 10-15m as a possible ceiling?

Of course, this is for the really hard core. Another, broader, proxy comes from the Root and ROM tools - apps for Android that let you mess about with arcane system settings. A scan through the download counts of the top such apps on Google Play points to, (as one would expect) a higher number. Superuser, for example, has had 10-50m downloads, as have several similar tools, while Root Task Killer claims 20m users but Play only reports 5-10m users, pointing to the prevalence of side-loading, especially in this demographic. There's clearly a lot of overlap here as well: few people will have downloaded only one. However, this data makes it hard to support an 'Android geek count' of much over, say 50-60m. If you assume a lot of sideloading (even of free apps) you might push it up to 100m, but that would be pretty tenuous.

These tools are still pretty hard-core, though. How about a more mainstream benefit of openness - such as the ability to choose your own keyboard? Well, Swiftkey has had 5-10m downloads. (It's also preloaded on some phones, but that's a different issue - we're looking at people who do this to their phones themselves). Swype, on the other hand, claims 250m users, and over 100m direct downloads, but those users are mainly due to a successful OEM preload strategy.

Meanwhile, I can say with a pretty high degree of confidence that there are around 800m Android devices in use outside China.

So, subject to all the obvious caveats, this enables two hypotheses:

Less than a tenth of Android users care that it's open

The number of people who care that Android is open is about the same as the number of people who run Linux

These are just hypotheses, of course - if anyone can suggest data that points another way I'd love to hear it.