OkTrends, the OkCupid blog about data analysis, is a great place to see what is possible with good data analysis. I think if you work in the field of data analysis, you should consider it a work obligation to read OkTrends.

One example of this is how they analyzed profile questions to determine which questions were both casual (easy to bring up) and strong predictors of compatibility. Read their post for the full analysis.
If you just want to cut to the chase, here are the key questions.
If you want to know if you and your date have long term potential, then ask:
  • Do you like horror movies?
  • Have you ever traveled around another country alone?
  • Wouldn’t it be fun to chuck it all and go live on a sailboat?
If you and your date answer the same way to all three questions, congratulations! You are 32% likely to become long term partners, compared to an average chance of 5% otherwise.
On the other hand, if all you want is sex on the first date, you just need to ask:
  • Do you like the taste of beer?
People who like the taste of beer are 60% more likely to have sex on the first date.