If my site would be on digg first page how much visitors I can expect and how much money $ I can earn from digg visitors
I've read you really don't make that much from digg. Most digg users will not click your adsense ads. However gaining readers and potential long term visitors is valuable. I've never gotten the "digg effect" however i've been stumbled and it didn't really raise revenues just lots of long term traffic.
I was once on the front page of a small time news paper site and I got around 19000 visitors 1100 clicks and $88 (my CPM is low). So, if your blog has high CPM then sky is the limit ... with a CPM of around 40 cents I could have generated $440. And, this site is not even as big as Digg is.
i've been on the front page of Digg.. Twice.. If i recall, i got about 70,000 - 100,000 visitors over about 2 days.. Adsense CTR was very, VERY low and i ended up taking the ads of the page(s). If you get a story on the front page of digg, the backlinks and ongoing traffic that you get are worth far more in the long run than the few dollars you might get in Adsense.. I got hundreds of backlinks, and now almost 2 years later, i still get about 1,000 visitors per week from Digg ..
The biggest benefit as Tearabite already mentioned is not just the traffic you get while on the homepage of Digg. Hundreds of sites linked to the story on our site after it hit the homepage as the story was quite viral and our traffic levels never dropped back down to the levels it was at prior to hitting the digg homepage.