…many successful consumer Internet services have three things in common that allows them to scale, get investor attention and, more importantly, bring in the much-needed revenues (and eventually profits).

Those things are:

1. They have a clear purpose.
2. They are simple to use.
3. They are fun to use or facilitate some type of entertainment or both

Now I don’t mean to suggest that you must have all three to be successful — but if you do, your chances of finding fame and fortune are much higher. 

When working on a piece, I ended up on this old Om Says newsletter — What makes a hit (consumer) Internet service. It is still valid, a year later.