LPT: Live support chat systems allow the business to see what you're typing in realtime, so only enter text you're 100% comfortable with.

Almost all support live chat systems provide a "Sneak Peek" feature that allows a customer support agent to see what you're typing in realtime before you submit. This can work against you if you're negotiating a resolution and type something (however brief) that gets taken the wrong way. Keep your in-progress thoughts outside of the chat!

ChatPirate
LiveChat
Salesforce
SnapEngage

Edit: vendor links