Longtail Keywords

I have seen a few posts on longtail keywords and I am fascinated by the concept. I know that many people really use this concept and have done quite well with it. The concept is really quite basic but it can have some huge payouts if followed properly. For example, if you are running a PPC campaign and have ringtones as one of the keywords. There is very steep competition on ringtones and you are going to pay a pretty penny to be ranked number one. However, if you choose something like ABBA ringtones, the competition for that keyword is not going to be as intense. And people that are looking for ABBA ringtones are going have a pretty narrow search and they are going to be more serious about buying ringtones if you can point them to ABBA ringtones. Chances are you are going to get better conversion ratios with the longtail keywords and they are going to cost you less to bid on. The downside of the longtail keywords is the fact that you are going to have less traffic, so you are going to need to have many more keywords to compensate for the limited traffic. I would be interested to see how many people are using longtail keywords and if they are seeing positive results from their testing.