I don't believe any of the crap they shovel on a daily basis. The only reason why they're mega successful is because they continually re-use their products and bring new one out of them.
Take
Basecamp for instance, the only real success
37Signals have, created by
David Heinemeier Hansson, the real talent behind 37Signals. Before David came along 37Signals was a web design/development company not specialized in anything product related. David brought the company into the whole web 2.0 scene, without him it's doubtful they'd be in the same position they are today.
Let's take a look at their products.
Backpack is a note taking/to-do's/file/photo sharing personal account you can have. Basecamp offers this, but for the clients of the Basecamp account holder. A stripped down product.
Ta-Da Lists is a note taking/to-do list that allows you to share them with other people. Backpack offers this, Basecamp offers this. A stripped down version of Backpack which is in turn Basecamp.
Campfire, their newest product to hit their little empire is original as far as 37Signals creativity goes. It's different, it's unique from their other products. And as far as I'm aware their other products don't offer this, although I wouldn't be surprised if it had slipped into one of them somewhere.
37Signals was not a product based company, they were usability design guys and nothing more, without David they resort to the same thing they were.
On the whole, I don't buy into their products, I don't buy into their presence anymore and I certainly don't buy into their ethics. I think it's totally wrong to offer basically the same application over and over again and charge people for it.