Our personal websites and our clients websites traffic is based on good SEO optimization. Almost all of our clients get their traffic 70% from Google or other Search Engine. But that's because we have a good strategy for SEO Optimization with best results. But definitely all should focus on traffic from search engine's that other ways like PTC. Best Regards MorFeaS
Stumble upon - 1- 2 k/day but it's really difficult to monetize If anybody has a solution to that please share
For most of my websites it is usually Google followed by direct traffic and stumbleupon referral. I also get a lot of youtube referral traffic.
Mostly Google, but I try very hard to get repeat visitors (which average about 50% of my traffic these days).