Stumbleupon limits?

Hi!

I am going to hire someone to make me a private bot for stumbleupon and I am trying to figure out the limits.

How to avoid to get the domains blacklisted, anyone who got a method that does'nt get the domains blacklisted?

I'm aware that I'm quite late to this, but in case anyone comes across this. I've used a bot as well, and submitted without a bot as well. I haven't been able to figure out any limits - even when other users had submitted, or when I submitted once a month, my website still managed to get banned from stumbleupon ( aka getting 0 views every time ) and when you contact them on getsatisfaction the answer will always be the same ( as you'll probably see others have done )