I have found some longtail keywords that have <100K competition but when I try to find out search volume both google keyword tool and SEO book say 'not enough data', which I take to mean nobody is searching for them. Would there be any point is going for a keyword like this? If nobody searches for them, what's the point?
I think not... if nobody searches for your keyword you won't get any search engine visitors, no targeted visitors.. or very little..
if the keyword is a long tailed keywords, you can search for the shorter version. Eg "how to save electricity" has not enough data, search for "save electricity" to see if there is anyone searching for it.
Basically "not enough data" tells about the impression & search volumes of the keywords/key phrases is not that much competitive.
You bet you should. Actually, it depends on the keywords/product. Go with your gut feeling. The keyword tools out there are not accurate, including Google. They give you whatever they want. Use them as a guide as opposed to written facts.) Don't be afraid to try it. The worst that can happen is that you don't get a gazillion hits. But then again, there is always the chance that you will get more then you think. I've done this quite often and have had good results. I've also fell on my face. But, it didn't cost me anything but a little time as I was doing article marketing. After awhile, you kinda get a feeling about it and can end up with quite a few winners.
It depends on what you are wanting to do. Getting more traffic or selling a product. For getting more traffic this keyword is not good. But when you want to use it to sell a product you should defenitely use it! Not enough data doesn't mean that nobody is searching it!
These kind of keywords have much less competition, but on the other hand, there aren't many people searching them.
If you think it is something people would search for, go for it. some really experienced gurus love those types. if it is a buying keyword phrase, (eg "buy specifc product") often the search volume will be low, but those people are looking to BUY! The only way to know, though, seems to be to try it.
Might be a waste of time to go after those keywords... there is such thing as picking the low hanging fruit, but this fruit is just laying on the ground.