Italics - you do it like (i)this(/i), Strolling Johnny - except that instead of those brackets - ) and ( - you use < and >, and it comes up like this
..............................

Requests for information aren't always just requests for minfirmation, they can be an opening to a conversation, and all kinds of unexpected infirmation and observations can arise that way. Often enough you could get the actual answer through a search engine, but that'd miss the point.

And the same goes for discussions - it may have been discussed many times before, but there are different people around this time, with different contributions to make. As WYSIWYG points out, going back and looking up previous threads is interesting in itself, and pointinh people to them is a friendly gesture most times - but it shouldn't ever be just a way of shutting up a newcomer, and occasionally it feels that way, and occasionally it is meant that way. Not at all nice.

Do people ever behave that way in the big world? "We talked about that three months ago, no point in doing it all over again."