[benologist]

You have to take it with a grain of salt - social games can and do make tremendous amounts of money but for every one that does a lot of others don't make squat.

Distributed Flash games also leverage microtransactions with varying degrees of success using platforms like http://www.gamersafe.com/ and http://wwww.mochimedia.com/, Mochi has a bunch of writeups at http://www.mochiland.com/. Andy Moore http://andymoore.ca/ and Chris Gregorio http://kaitol.com/ have both been very frank about their numbers although neither has implemented microtransactions yet.

A Russian developer called Badim has a long-running series of posts about his experiences leveraging microtransactions from various providers in this form of gaming: http://blog.elite-games.net/blog4.php

In terms of market size the numbers are enormous anywhere you look - I track games on and off Facebook, with and without microtransactions, that have 10s of millions of views.

The real key is very simple but ridiculously hard - you have to make a game that people want to play. The people making serious cash off social gaming are ultimately doing it because people really want to play the shit out of their games, and most games of any type or characteristic simply do not enjoy that status.