Ask HN: Is there a directory of business web apps?

My friend has a startup (www.olyfe.com) and he is looking for some good quality web apps that can help him run his startup in a more efficient way. I've seen some great weekend projects and other startups posted here on HN and then just fade away from the homepage.

Some I dont even remember what they do. Is there a database of these startups ranked by popularity/age/quality that I can find to help him run his startup more efficiently?