I know this may seem a bit vague but when your talking to someone online (if they answer back). Then do you need to flirt and stuff so something can happen or do you need to be friends first or something? Because all my conversations so far have just died.
I think it rather depends on who you are talking to and for how long...and which site you are using probably! I'd also like to know the answer on the off-chance anyone sensible ever messages me!
In cases like that, I just keep talking about things we have in common and events that are happening in our lives. Both sides keep the conversation going by asking questions in their response that relate to the conversation at hand. That way, the other person has something to go off of when they respond to you in turn. Yea, flirting may eventually grow out of this. However, to start initially flirting with each other would be a bit odd in my opinion...considering that you've never technically "met" each other. It's best to get to know someone before getting all flirty with them (Better relationship-wise anyway. If you're looking for just a hook-up, then fast flirting would probably be more appropriate).
Chemistry transcends the electronic barriers, If you haven't found someone that will find you attractive on what you've given so far, Then you've simply just not found the right person, I wouldn't change my behavior(Unless it's rude or maybe very bland). Best of luck!