It is a fairly small website developed just by myself. I don't think I've ever characterized it otherwise.
> The [Pinboard] fee is based on the formula (number of users * $0.001), so the earlier you join, the less you pay.
The current price is $9.22, so following this formula he has ~9220 users, which has paid him roughly 42K. He also charges $25 (minus your sign up fee) for archiving, which would bump that number up a bit.
I want the freetext search, but don't need to be able to access the archived page (except for the equivalent of Google's text cache if the remote page is down).
So yes I want archiving, but I don't need asset archiving for things like the images, css, javascript on the pages. And yes I realise for a lot of hashbang sites this would break, but that's just dandy with me.
I could sign up to the archiving, but with over 1,700 bookmarks I hesitate... will it go and download all of them? I think that's creating a burden on your service so I am not upgrading. I'd even pay the same price, or damn near it, as the full archiving, but I really want to get the fulltext search in a guilt-free way.
It comes down to this - storage is cheap and development time is expensive. It would take considerable work to retrofit the crawler to only fetch dependencies for certain users, manage the case where they upgraded/downgraded between levels, and so on.
It saw a huge influx of users the day the delicious end-of-life-ing was announced, and held up admirably.