I'm getting a huge amount of traffic from stumbleupon 90% and organic 5% to 10%. Is it ok with google adsense or will they ban me?
Google gets suspicious of sudden spikes in traffic. Let them know if you are picked up by a news story. This usually result in a boat load of traffic and clicks on adsense.
If everything is genuine, then you need not to worry. I do not think that the traffic from stumbleupon will create any problem for you. BTW, how you arranged that traffic?
You probably will not get banned but from what I understand that kind of traffic (as well as digg traffic etc) is not great for clicks
Yes. Of course. That traffic was ok with Google. Don't worry about that, my friend. Try to optimize and target traffic more. It will help you so much !!!
Focus on your organic traffic more, the problem with stumble is it only comes in bursts. So this week might be great and next week stone dead. Optimise your site to rank well and focus on ground SEO rules.