The biggest problem for SO in terms of monetization is how freely available their data is. For example, if you simply want an answer, Google itself will extrac

The biggest problem for SO in terms of monetization is how freely available their data is. For example, if you simply want an answer, Google itself will extract the top 1-3 answers and present them to you without ever opening SO. Further, SO has explicitly avoided the most intrusive advertising, further limiting their monetization potential. The one area where I think SO could have done a lot better was building a better social network out of their website.