[font="Calibri,Arial"]I assume it's something like using a different font, or a different colour for your posts except less subtle (well, I wouldn't call some of the colours in use subtle but that's a different matter).[/font]
I never sign my posts unless its for something inspirational or dramatic. The urge could come from emailing frequently, because they require you to be more formal than forum talk. As for me, the people I deal with through email are mostly adults, so I am obligated to show respect. If I didn't, I would't be popular in my Council.