I recently read an interesting article by Daniel Negreanu about talking at the table. The article explains that when you do chat away at a table, you can get information about an opponent's hand but you could also gice away too much information on your won hand. If you use it properly and against the right opponent, it's worth the effort.
The atricle lays out several rules:
1. Don't attempt it if you are a beginner. You need focus on fundamentals. More experienced players usually prevail when you get into a table talk psychological attack.
2. Don't talk at all. You probably be better off sitting still and be quiet unless you think you get your opponenet to do whay you want him/her to do.
3. You should throw your opponents off by sometimes telling the truth and lie. You need to lie effectively and do it the same way as telling the truth.
4. Don't leave patterns like talk when you are bluffing
and staying quiet when you have a good hand. Good players look for these patterns.
5. Be relaxed when you are chatting becuase you would be able to get your opponent to do the same thing causing your opponent to be less aware of the information he/she is giving away. If you're relaxed when you're talking to your opponent, you increase the chances of him being the same. And when he's relaxed, chances are he'll be less conscious of what information he is giving away.
6. Do use it towards weak players.
Above all else, do not be rude or mean in any way. As the article explains, "being a jerk at the poker table does not help your bottom line. People are generally a lot looser with their money when they're having fun."