I've been following tarsnap from afar and think it looks like a great service. That said, an "unprofessional" look & feel is a deterrent for most people because it implies the service may be unprofessional (people tempted to click away before diving in to see whether you're qualified).
Think of it like the crackpots who submit their own math/physics theories. Sure, a professor can critically examine every submission, but it's not a good use of their time. It's easier to just read results in refereed journals.
If someone eccentric is doing something truly groundbreaking (Perelman solving the poincare conjecture), then most people expect somebody to tell them about it. Craigslist is like this -- if you saw the same layout on bobslist.com, you'd know it was some rinky-dink site. But craigslist built a reputation and that reputation is what made it spread.
Unsolicited advice, but long story short: people make snap judgements to save time, and often times they are correct (I suspect most unprofessional-looking sites are not run by professionals in that domain). This can be overcome with word of mouth, but it's ideal to not have to "overcome" their initial snap judgement and make a good first impression.
Think of it like the crackpots who submit their own math/physics theories. Sure, a professor can critically examine every submission, but it's not a good use of their time. It's easier to just read results in refereed journals.
If someone eccentric is doing something truly groundbreaking (Perelman solving the poincare conjecture), then most people expect somebody to tell them about it. Craigslist is like this -- if you saw the same layout on bobslist.com, you'd know it was some rinky-dink site. But craigslist built a reputation and that reputation is what made it spread.
Unsolicited advice, but long story short: people make snap judgements to save time, and often times they are correct (I suspect most unprofessional-looking sites are not run by professionals in that domain). This can be overcome with word of mouth, but it's ideal to not have to "overcome" their initial snap judgement and make a good first impression.