When you click the quote icon on a discussion page this shows up (using my name as an example):

[quote="Paddy Cummins"]

Then, the quote follows, and the end quote code ends it. But the colon and number following my username is not needed I realised. I could just quote somebody by putting in [quote="Paddy Cummins"].

So what do the numbers stand for? Is it member i.d number or something?