i don't think there really is any chemistry
even if u talk its not as if your spending time face to face
what if the person is lying to you and is doing it for a laugh or pretending to be someone they are not.
i don't trust meeting anyone on the internet just to be VERY safe
If you can keep a relevant conversation going then that is a good sign that the two of you may have good chemistry together. However, there are alot more factors involved when meeting face to face. I made it a point not to communicate with someone over the internet first and meet them later. It saved me from alot of awkward moments.
if you talked to me online your are in the same danger as a sexual predator was talking to you. even if you have talked for a long time these things are a reality. I hope its a supported site like eharmony or something like that.