Here's the thing. Think of the internet (MSN, Lavalife, etc) as just another means of meeting someone, just like a night a the bar. That's all it is, a vehicle to meet someone.
After that it's no different than "traditional" dating. It's all up to you and your personal skills. How you talk, how you act, what you say/write doesn't change much from "normal" dating. The Internet isn't going to help you if you have the interpersonal skills of Dion Phaneuf.
I find it interesting how people think of Internet dating as some sort of completely different animal than "traditional' dating, with different rules and space age techniques. Really, it still boils down to you.
I did mess around with this for a period of time (not any more though). While the above holds true, you certainly do get to see a greater cross section of the dating population than "normal dating. The women I met when I was into it trended into categories: (just like "normal dating" I might add)
1) The Jaded - broken up with boyfriend from an engagement / long term relationship. You're not going anywhere with this. Tough nut to crack as she'll always have her guard up.
2) The Serial Dater - is currently has about 6-8 men right now. Not sleeping with them all or anything, but certainly is enjoying the attention and "fun" side of dating (being wined and dined). This more than anything is higher in Internet dating than it is in "traditional dating". Not interested in a relationship.
3) The Casual Dater - just wanted to see what this Internet dating thing was all about. Might answer emails sporadically, or not at all. Often is a "hot" girl, just curious to see what's other opportunities there are.
4) The Ego Builders - would post a ridiculously hot photo. Probably had about 50 emails a day. Would morph into 3) above.
5) Self Esteem builders - saw this a great way to meet people without being disadvantaged by that fact they might not (with all due respect) be all that physically attractive. Posts somewhat misleading photos.
6) The Nympho - as 2) above, but sexually active. Lots of talk about how much it means to them. Not good relationship potential though.
7) Damaged Goods - herpes, $18,000 of credit card debt, various mental disorders (eating, psychological, etc). Some people like to use this as an opening line to put this on the table, and "take me for what I am". I don't want to sound callous or insensitive, but it's not exactly what people are looking to get into (at least I wasn't, and had to extracate myself with care, as as not to hurt them).
8) Normal - These truly do exist -sometimes you'll find someone actually interested in a relationship. Just like "normal" dating you'll have to seperate the wheat from the chaff, and it's certainly not easy. They're out there!