No cgraz is dead on.
If one cannot meet in person with a woman, the only *reasonable* method of indirect interaction is the TELEPHONE.
Let's take one step back here, and first detail the advantages of the first hand contact (real life meeting).
- the TACTILE (KINO)
- the VISIBLE (body language, physical appearance)
- the AUDIBLE (tone of voice, inflection)
With the telephone call, the scenario changes to this:
- the AUDIBLE
This is minimally adequate, but it is acceptable because it really lets you focus on your vocal skills. And in certain cases, this is GREAT way to get her warmed up for a date (first or subsequent). You can make her laugh, and give a good impression and warm up her engine for when you do meet. Also, the telephone creates this weird intimacy where you super-tune all your senses to your ear. You are paying close attention to her voice, so you can read her mind, her wants, her desires. You can fine-tune your ability to manipulate that over the phone. I can recall several times where some excellent phone convo (yes... even ones upto an hour long, belive it or not) let to some great dates and some after-hours action.
NOW... with IM, the best you have in your arsenal are cheesy emoticons.

That is very weak. All human indicators of warmth, closeness, and intimacy are completely gone. You cannot use your tone of voice to manipulate her; nor can you gauge if she is REALLY amused by your joke or just being polite (How many time have you used "lol" without really meaning it? Think about it.). She could also be talking to people other than you.
Just about the only advantage I can think of is being able to carefully measure your words for good effect, but if you're good with people and women to begin with, this shouldn't even be an issue. The trade-off between the intimacy of in person meets and phonecalls, and the ability to plan your speech on IM is too great.
Therefore I strongly concur that IM is for complete newbs or dorks with little social grace. Then again, there are plenty of 'newb girls' and dorky girls with no social skills, and I'm guessing that more than a few guys here don't even shoot for the super-hot chicks to begin with. They probably go for the reasonably cute girl next door type, so it's no big deal. IM-ing could work for these types of girls.