I have done the online dating thing off and on (mostly off) for the last 3 years. I went on several first "meets" can't really call them dates which were good opportunities to get a feel for if there was any spark or attraction (which for me is extremely important) between us. Two of these turned into multiple dates with one being about a 4 month relationship. However that relationship did not really grow past the initial infatuation and newness and excitement that comes from being with a new person. I think that was primarily because I wasn't really, really ready to let someone else in (yes even men feel that way - it's just not about hooking up). However, it is clear I am ready now and as a result I have started a relationship with someone who I have the kind of feelings for that I haven't had since dating my ex-wife - which is really nice and promising. I wouldn't say I am "in love" yet, but the relationship is moving steadily in that direction and I couldn't be happier. Long story short is that I think you have to be ready to let someone in completely before you have a chance at a successful relationship with them. Just my 2 cents.
