I don't generally converse, and don't expect it, either. But if someone says 'hi' I will respond.
As for waiting until the last quarter-hour, well, it wouldn't bother me if I was on the other end of that.
I DO think it would be good manners to let your opponent know that you are retiring or taking off for awhile if you have played a few moves 'live' on a 1-day or longer game.
OK - so I don't particularly want everyone's life story, I do like to say "hello" or "good luck" or "how do you do?" to my opponents at the start of a game.
If they don't have the decency to hit 3 keys (h, i, and <enter>) to reply, is there any reason I shouldn't make them wait until the last quarter-hour for every move?
I've also seen an instance of innappropriate language on the forums tonight. It's not too encouraging, especially when my kids are asking to play on this site.