I'm not sure how much of that would actually be doable - for example, I don't think portals and mage tables will be traceable back to their owner when you use them.
Trading would probably be doable, but it would be problematic - you could end up thanking people when they should be thanking you. And the same goes for tipping.
You might want to have a look at one my addons, Thanks4Buff (
http://www.wowinterface.com/download...anks4Buff.html), which does - well, exactly what it says on the tin, really. It thanks people for buffing you - although not party and raid members (as that'd get very spammy).