This site is self-touted as the social bookmarking service for introverts. The impression one is under after browsing through the provided documentation and having a look at the featured stories is that it aims to stand as a smaller social sharing environment.
That is, it intends to avoid the pitfall of other bookmarking sites where the content spirals and a thousand items are submitted per minute. The emphasis of Pinboard is keeping track of just some interesting links, keeping everything easily accessible and reasonably fast.
Moreover, in order to keep spammers out of the picture as much as possible a small fee must be paid in order to start using this service. It is a small, nominal fee, but such a practice is known to work well and discourage those who do nothing but clutter everything up.
Other than that, the site is available both in English and in Spanish, and the translation is quite good, I must say. Give it a try and see if you like this streamlined approach, and whether or not you find it more fulfilling than browsing sites like Digg in order to find items that could appertain to you.
Pinboard.in In Their Own Words
“Social bookmarking for introverts.”
Why Pinboard.in It Might Be A Killer
The ones who are adverse to “major” bookmarking services will take a liking to it.
Some Questions About Pinboard.in
Will it catch on? How can the service advertise itself? 
