There are probably more than 10 "anticafes" in Saint-Petersburg(as "Ziferblat" had great success after opening in early 2012). Some of them are profitable, AIK. Ziferblat is the good place for hanging out, but too noisy to work(many students playing table games around). If you want to work, better choices are "3rd place"("tretje mesto"), me4ta.tv(far away from center, but best choice probably if you're staying in northern districts of the city) or even IMarussia.

P.S. In Saint-Petersburg's Ziferblat, you can take coffee-to-go for free but donations are highly welcomed.