So I'm making a profit using glyphs, as many of us are. For story sake let's just say I put up a glyph for 20g, I find I have another in my bank, I go back to the AH to see what I put it up for, and I see someone has undercut me, by a lot. My 20g glyph has been undercut by three of his same glyph which he intelligently put up for 5g. I ask in trade (now I've learned this is the wrong thing to do) why someone would undercut by 1/4 the price of the next lowest item, and I proceed to be called a noob for "not buying out his" (which I did) and proceed to be called various names of which I can't say on these forums due to them being against tos.
Trade chat = troll chat. Never ask a question in trade! All the servers I've ever played on are the same that way. You might get one helpful reply (if you're lucky) and 20+ insults, not worth it.
The reason the guy undercut you is either, a) he's trying to catch out people using bots/automatic posters to make them list theirs cheaper to buy out, b) he wants to move shit seriously quickly and doesn't care about a small profit, or c) he's pissed off at people making high prices and is trying to make a point/lower the market. Either way it doesn't matter, wait till his sell or buy him out and relist and profit