I just notices that my site is at stumbleupon.com as i checked the traffic is from there.... I tried to find my site there but unable to find... what will happen
You will get good traffic, your stats will go up, but stumble visitors are good at not clicking any ads, so your ad revenue may not increase significantly. However, if you have good enough hosting, it can never hurt. The more people get introduced to your site, the more potential future traffic you can get through second hand referrals.
what part of the site is receiving visitors? Whatever the url is add this in front of it. http://www.stumbleupon.com/url/ for example http://www.stumbleupon.com/url/google.com or http://www.stumbleupon.com/url/www.google.com or http://www.stumbleupon.com/url/http://www.google.com or http://www.stumbleupon.com/url/http://google.com
i saw mostly from refer.php Your page is on StumbleUpon One of our members added your page to the Unknown topic on StumbleUpon. Each time our members who are interested in Unknown "stumble upon" your page using our toolbar, it will record an entry on your referral logs.
Try blending your ads and don't rely solely on AdSense. If you place a relevant banner that they see, your traffic may not become useless. Be happy you are getting traffic, as it all has potential to make you money.
lol There are too many ways to even list. Get backlinks to your site, have quality content and get ranked for your targeted keywords and you will get traffic. That is just one out of about a thousand ways to get traffic. Search around a bit to find more.
There were cases when SU traffic got a publisher banned from adsense, but it doesn't mean it wil automatically happen. It has mostly to do with the fact that SU traffic doesn’t click ads and adsense will see high traffic, but no clickthrought so they may think something is fishy about your site. But it doesn't mean each site that gets popular on SU gets banned.