Good question. I think it's a 50/50. 50% are not serious and are just rambling for the kicks, for the fun of it to get more hits to their websites, hubpages etc. and the other 50% ask real meaningful questions and others give real meaningful answers but they have a different approach to possibly receive more hits however honestly getting interaction with others over all, questions can be answered.
Making a connection is the key because people in general can sense the real reason why people do what they do after some time.