The long tail of a market is not directly related to the number of keywords.

This is a common misconception.

Long tail doesn't mean - lots of keywords.

The number of keywords depends entirely on the niche you're operating in. The tail goes on forever, so you can pick how far along you want to go.

If you're in the music niche - long tail might just mean very niche cult status music - it could still be one or two keywords.

The meaning of the long tail is related to the segments with lower and lower demand. The stuff that if you had to stock items on physical shelves you wouldn't give the space to because it's not popular enough.

On the Internet you can go as obscure as you want, so there are no limits.

The keywords just represent what people are using to search for those long tail niches, so there is no set number of keywords relating to this subject - it all depends on the niche.

The point most marketers are relating to with long tail keywords is search terms with less searches - that doesn't mean the same as long tail - so sometimes people get confused because of the misuse of the terms.

If you know your market and its sub and micro-niches you should be able to find some long tail phrases without too much trouble - just don't confuse it with terms that don't get searched much or you may end up wasting your time.

Andy