In Reply to: I've got a TL for you posted by Barbara Makature on August 16, 2008 at 15:48:
I found an answer myself and want to share my findings. T.L. is short for 'trade last' which the dictionary defines as:
A favorable remark that one has overheard about another person and offers to repeat to that person in exchange for a compliment overheard about oneself;
a compliment that I heard about you that I offer to trade for a compliment you have heard about me.