[bluethunder]

There is really no way to know. Your product might be just one iteration away from making it big. There are products which take time to hit the up-curve on the hockey stick - case in point gmail.

This is the hardest part about entrepreneurship and as Ben Horowitz puts it in one of his posts - no amount of pattern matching can help. These decisions can only be made from the gut - and basically need to align the entrepreneurs longer term motivations with 'his' understanding of the individual merits of the business.