What I've found is that there's almost always some people that want any particular thing. The two really big questions are 1) How many of them are there? 2) Can you make money off them?
#1 is much tougher. If you're in a niche inside a niche inside a niche and you end up with 10 paying customers sending you $20/mo it's technically "working", but too small to be worth it.
#2 is easier. The situation Twitter is in. They have tons of users and now it's purely a matter of ingenuity to come up with a way to profit in a big way.
Comments
What I've found is that there's almost always some people that want any particular thing. The two really big questions are 1) How many of them are there? 2) Can you make money off them?
#1 is much tougher. If you're in a niche inside a niche inside a niche and you end up with 10 paying customers sending you $20/mo it's technically "working", but too small to be worth it.
#2 is easier. The situation Twitter is in. They have tons of users and now it's purely a matter of ingenuity to come up with a way to profit in a big way.