I don't understand either why many are suggesting you get a cofounder. You just need another person who can work on UI, branding, PR, etc. Don't give them any equity, don't give them any control over the innards of tarsnap, just pay them a handsome wage (for the handsome job that they'll do).

p.s.: in my ideal world, you are every founder (doesn't partake in shitty, ethically-questionable growth-hacking techniques), and your company is every company (offers a decidedly great service, no gimmicks). I think it's extremely unfortunate that you have to do these extra things to be successful on the next level... I wish things weren't this way. But unfortunately you do have to play this strange ballgame to get there.