Marc Hedlund, founder of the intriguing Wesabe, recently made this interesting observation:

One of my favorite business model suggestions for entrepreneurs is, find an old UNIX command that hasn’t yet been implemented on the web, and fix that. talk and finger became ICQ, LISTSERV became Yahoo! Groups, ls became (the original) Yahoo!, find and grep became Google, rn became Bloglines, pine became Gmail, mount is becoming S3, and bash is becoming Yahoo! Pipes. I didn’t get until tonight that Twitter is wall for the web. I love that.

A slightly related way of thinking about how to choose web projects is to take something that everyone does with their friends and make it public and permanent. (Permanent as in permalinked.) Examples:

Blogger, 1999. Blog posts = public email messages. Instead of “Dear Bob, Check out this movie.” it’s “Dear People I May or May Not Know Who Are Interested in Film Noir, Check out this movie and if you like it, maybe we can be friends.”

Twitter, 2006. Twitter = public IM. I don’t think it’s any coincidence that one of the people responsible for Blogger is also responsible for Twitter.

Flickr, 2004. Flickr = public photo sharing. Flickr co-founder Caterina Fake said in a recent interview: “When we started the company, there were dozens of other photosharing companies such as Shutterfly, but on those sites there was no such thing as a public photograph — it didn’t even exist as a concept — so the idea of something ‘public’ changed the whole idea of Flickr.”

YouTube, 2005. YouTube = public home videos. Bob Saget was onto something.

Not that this approach leads naturally to success. Several companies are exploring music sharing (and musical opinion sharing), but no one’s gotten it just right yet, due in no small measure to the rights issues around much recorded music.