I don't really consider Tarsnap to be in the same category as those. Sure, I think Tarsnap is a fantastic online backup system; but that's rather subjective. If/when Tarsnap becomes wildly successful, I'll be able to make the objective claim of "I started a company which (is making $X/year profit | I sold for $Y | has N customers | etc. )" but until that happens, Tarsnap isn't really something to "brag" about.