When people ask me why I think I can do this, the fact that I built and run portsnap is something I often mention -- of course, 50k people using a free service for updating FreeBSD is different from people paying me to store their backups, but at least it demonstrates that I (a) can build a system which scales into the TB/month range, and (b) am able to "make something which people want". I also developed quite a few ideas while working on portsnap which I'm now using in tarsnap... hence the similarity in naming. :-)
But you're quite right about people being impressed by open source credentials -- I've had a few emails along the lines of "I only have a vague notion of what you're doing with tarsnap, but I've seen enough of your FreeBSD work to know that anything you do is likely to be good -- so let me know if you're looking for investment". So far these
have all gotten a polite "thanks, but I'm not looking for funding right now" reply, of course.
But you're quite right about people being impressed by open source credentials -- I've had a few emails along the lines of "I only have a vague notion of what you're doing with tarsnap, but I've seen enough of your FreeBSD work to know that anything you do is likely to be good -- so let me know if you're looking for investment". So far these have all gotten a polite "thanks, but I'm not looking for funding right now" reply, of course.