Om Malik writes about how Engage, a dating website, backed up by serious people, started off quite good but got flatlined after a while.

This is a very interesting phenomena in my view, that many young companies fail to overcome.
Everything starts great, you get the right coverage, users start to use your product and you have that “viral feeling” in the air.
And then it stops.

Why?

One reason is because the users that are the first to use your product, aka (very) early adopters, are not the users you need to acquire later on.
And what do I mean by that? Early adopters are great; they are willing to try everything, and they will tell it to their friends - for good and for bad (meaning that if your product sucks you are in trouble from day one…). However, being so open to try new stuff also makes them dump your product quickly. They are not staying around for long and they have almost zero loyalty. Because of those reasons, and because they are a relatively small percentages of the population, you reach the “flat line” very quickly.

Most startups are trying to have a conversation with their users in order to better understand how to improve the product / service / experience. Which is great - just keep in mind that at this stage you are talking to early adopters, and they will mainly tell you how to get, well, more early adopters.

Don’t get me wrong, early adopters are extremely important and in fact, without them your chances to get to your main audience are poor. You must talk and learn from them, and at first you must even aim your product to their needs. But once they got it, you need to move on.

How?

I highly recommend reading this classic book: (and other books of Geoffrey A. Moore).
It provides an in depth analysis about different user types and how to advance from one stage to the other.