As a full-time Mac user for 8 years, and a Linux user for much of the decade before that, I am acutely aware of how common many filesystems, including HFS+, actually are.

If OS X ever breaks 10% (and still uses HFS+ at that time), I'll reconsider my judgement of its commonality.

I'm writing this from a computer with two partitions: one HFS+ running OSX and one Ext4 running Linux. These are both the default options when installing OSX (Mountain Lion) and Ubuntu 12.04, respectively:

https://www.dropbox.com/s/x3cluigwaog8sad/gparted.png

Of course you are. And if you took a poll of HN users, you might even find OS X + Linux near a majority. That has nothing at all to do with what filesystems the vast majority of people are using, much less what they'd be using with TrueCrypt.

It's over 7%, I still wouldn't call that uncommon and say few people use it.

http://en.m.wikipedia.org/wiki/Usage_share_of_operating_syst...