[10ren]

Not just exposure, but exposure to the right two communities: many designers follow them, and many coders. These groups tend not to hang out (like biz and coder guys don't...). If there aren't any other intersections, it's a unique competitive advantage.

Perhaps the trick is also in knowing what you got; and what problems others have got.

hmmm... I do wonder if some kind of specific advertising like this was a thought very early on for them when they started dedicating themselves to blogging, speaking to build an audience, as a financial rationalization of what they wanted to do anyway. :-)

[dpcan]

Yes, they will get sign-ups because designers and coders know about them. But if I went to ANY of my web design clients from the last 7 years, I would have to say that maybe 1% or less of them EVER heard of 37Signals.

That being said, it looks to me like a bust in the making because if only other designers are looking at your $100 per month "ad", then it's actually working against you.

[10ren]

I was thinking that coders need designers; but you're saying that, in fact, clients are neither.

hmm.. I bet that some coders do need designers (e.g. if the coder was hired first), but it's probably a tiny tiny fraction of all clients.