I've nopticed this creeping into more and more posts. I've only just found out what it means. When did this start happening and why? Or have I just been asleep for a very long time?

what does it mean then.?

Urban Dictionary is your friend: 'Your Mileage May Vary' or you could use YRMV (guess what that means 🙂 )

Much quicker to type and most people know what it means, 'tis basically a caveat innit? 😉

It has been around for years, I remember seeing/using it on usenet.

Like psychle says, it is a very handy shorthand disclaimer/caveat thingy.