The best way of getting information about any specific career is still to go out and talk to people that are already practising in that career. Since that's not always feasible it's important to have other sources.
I have mentioned that quite a number of people are predicting that careers in 'big data' will become more numerous. That is probably why this item on Quora caught my eye: How do I become a data scientist? It contains some very useful advice.
Most of us are aware of LinkedIn as a place to ask others about career prospects, although I have found that it's important to filter answers from LI to omit those that do not come from people with real experience. Peeling back the URL provides the address of a collection of Quora Q&A that might also be a useful source: http://www.quora.com/Career-Advice.