I certainly like it better than the glossy competitors with their sneaky marketing-speak and buzzword bingo.

Thanks! The google-like "clean" style is very much what I was aiming for.

You have a point, though, in that he should explicitly put 'sans' in his CSS for the 99% of the population who can't be bothered to change their browser default font.

Ok, that last one is facetious -- but in all seriousness, I'd love to hear something more specific than "unprofessional".

- "can probably be compiled on many other UNIX-like operating systems" comes across well from one nerd to another, but probably not to managers. This gets into the question of who your target audience is.

- In the intro, talk about what tarsnap does instead of just saying it's a secure online backup service and talking about the "client code". What makes you different from the hundreds of other backup services?

- The red yellow and blue color scheme isn't doing it for me. Looks better if you make the red yellow, but I know you want to draw attention to the call to action.

- The gap between the left column and the news is ugly. Consider not having news on this page at all.