In the latest entry on his Pinboard blog Maciej Ceglowski reflects on the first six months of the bookmarking service, citing his novel business model–the sign-up fee goes up by ¹⁄₁₀^th of a cent with each new user–as the key to scaling the site and keeping out the spammers.

I’ve used Pinboard since the day it went public, and have been impressed not only by the site’s simplicity and reliability–it’s certainly acheived its goal of cloning Joshua Schachter’s del.icio.us, as opposed to Yahoo!’s delicious–but also by the very careful addition of new features (delicious, Instapaper and Twitter integration) which work flawlessly if you choose to use them, and stay well out of the way if you don’t.

The latest feature is intriguing, too: for a $25 annual fee, Pinboard will archive a copy of every web page you bookmark, effectively creating a personal Internet Archive.