[thenomad]

This is radically different to the above questions (which you may not find personally useful, but to the more bootstrap/entrepreneurially minded HNers are often pretty helpful or interesting.)

They are general information/discussion posts.

This post's a direct service connecting HNers with assets to HNers who want to buy them. Assuming there are a reasonable number of both, and the replies in the thread so far suggest there are, it's useful to have it recur for the same reason that "Who's Hiring?" is useful.

As for your question on whether anyone's ever bought a side project from a thread like this - the comments on this thread alone suggest there's a fair bit of interest in purchasing side projects, at least.