[NameDrive]

If you own a domain that is an excellent generic it will likely get traffic because people assume that it must be a site, thus they will navigate there directly.

If you have a domain that is a typo of the above 'excellent generic' the same would hold true. You'd likely get traffic.

If you have a domain that is a typo of an existing site, you will likely get traffic accidentally.

If you have an expired site--a domain that used to be a popular website and for whatever reason dropped to you--you'll likely get traffic.

There are a number of other domains that could wind up with traffic, but these are just the obvious, easy-to-explain ones.

Cheers,
Lucas