Yeah, active Pinboard user as well, coming from del.icio.us a number of years ago. Have 35,549 bookmarks in Pinboard as of right now, will almost certainly be a bit higher by the end of the day. Definitely a personal knowledge repository. I can't tell you how many times I'll be talking to someone and say, "You know, I read an article about that a few months back... let me send you the link" - really useful. I also like when I save a really good link and see that others have linked it too, and then I can explore what else those folks have bookmarked with that same tag; it's a great way to find other high-quality pages. Kind of "social bookmarking" :)