They had an about average size blog for the time. It's definitely not like their fame preceded or enabled their success. It's the other way around.

They've explained this on multiple occasions when people ask them how to repeat their success without their advantage of having a big audience and (relative) fame: they didn't have that when they launched Basecamp.

They had a blog, but not a huge audience like they do now — they certainly did not have a bigger audience than is possible to build up through "traditional" blogging means (writing great content that people like to read and link to).

I'm not convinced. I'd rather see a series of case studies of small and successful firms that don't have something like Rails or a huge following (and what other word to describe some of the people who comment on their blog... some of them are really falling all over themselves to sing praises to 37S).

What are you not convinced about? That their current following hasn't been that big since the dawn of time?

37signals is an excellent case study of a company which has built a profitable successful business without any kind of fame or following. Because they weren't famous and they didn't have a big following and Rails didn't exist, way back in february of 2004 when they launched Basecamp.

They go on and on about how small and simple they are, and how they do less, and so on and so forth.

However, small, simple, and few features makes for a very low barrier to entry if that's all they have, so I'm not sure it is a very good model unless you are famous like they are (that's their "barrier to entry"). In other words, they are something of a special case, not really an example to be followed, even if what they've done is admirable.