What serves this purpose with a web app? Is it a stock photo of a person? (Doubt it.) Some bit of humor that a corporate marketdroid would never write for fear of pissing off his boss? The developer blogs? MySpace or Twitter presence? I suspect that most of the time, most of these things don't succeed.
Perhaps this is part of the power behind "Viral Marketing" in the old days when its effectiveness wasn't diluted by so many trying the same thing.
A real, honest to goodness, here we are, this is my desk, good-and-bad blog?
I signed up with Dreamhost because I truly felt they would care - their site is very good at giving that impression. Their service was poor, so I left, but that's another story.
Twitter presence is a new thing, but it certainly helps.
In the past I've found having an IRC room or a forum to help. I've chosen hosting providers this way and it's worked out every time. If they can answer my question on their IRC channel and have a bunch of dedicated followers (dedicated enough to be sitting in their IRC channel anyway!) that's a really good sign.
It's my personal feeling that most people can tell the difference between "calculated humanity" and real humanity. Most businesses and startups go for calculated humanity because real humanity is something they either don't believe in as an aspect of business, or are afraid to show because omgz what if somebody says something the readers don't like?
Real humanity means being vulnerable and talking about negative stuff, and risking people not liking you. But the people who don't dislike you will like you more. It means being genuine, not just "authentic."
When I left my parents as a teen, I partially supported myself with a Mac news/opinion site. Everybody told me that there was no room for another one, blah blah, but I decided to write like a real (& funny) human being instead of pretending to be a professional journalist like the rest. I earned $600-1000 a month in ad impressions, so it clearly worked.
Same thing worked for my current web site & information products I've created. I'm totally famous in the niche, and I'm not the best or brightest with the actual programming aspect. But my oldest tutorial from 2005 still gets about 15,000 views a month.
When it comes to my new SaaS that I just launched, it's the same thing. The blog is "real humanity" and I answer support requests myself.
Perhaps this is part of the power behind "Viral Marketing" in the old days when its effectiveness wasn't diluted by so many trying the same thing.