I actually find it impressive still. The reason being that for companies as big as they are to actually allow to use a new product has to go up high a couple of levels, and needs a lot of approval. So if it made it all the way up, and it was approved, even for that "one guy", it means there is a future in the company for the product.

That would be true is Basecamp was a $500 a month product, but since the price is so low it falls within being a cost that can be expensed. That expense level is usually a few hundred dollar per month, before it needs approval.

Joel Spolsky wrote a post about this[1]. He had a great point - either price your product under the expense level, or if you prive it higher - go all the way and price it as an enterprise product, since it will involve a chain-of-approval, a sales cycle etc.

The other good example is Atlassian. They prices their products so that they can sneak in as expenses. The founders talk about how with a lot of their customers the bosses do not know that their products are being used. It is a way to sneak into an organization through developer love and being a line-item in an expense report rather than something that is bought and procured.

[1] Camels and Rubber Duckies - http://joelonsoftware.com/articles/CamelsandRubberDuckies.ht...

It's not clear but it looks like they're also counting people who just signed up for the trial version.