I've been running the market for so long but i noticed that much, much gil from what i sell is given to taxes. My questions are:

1) If i put something to sell in Ul'dah market, is it visible by someone who checks the market from LL?
2) Is there a fixed tax for each market, if yes, how much?
3) Tax rate affects amount of things for selling? I constantly keep my retainers full in terms of selling capacity but if this is the case i might not gain any profit at all.
4) Why is there a tax after all?

Thanks in advance