Pinline ($2.99) by Lapdog is a more recent addition to the list of iPhone Pinboard clients for iOS, adding to the pile of other apps like the classic Pushpin, the fresh and universal Pincase, and the fast and light Pinswift on iPhone.
After grabbing a Pinboard account, which will run you a one-time fee of $10.29 as I write this sentence, you can start collecting bookmarks from across the web and use one of the few apps that I have already mentioned. However, after trying all of them for myself, Pinline is the best fit for how I use Pinboard, and here's why.
Pinline presents the bare bones of Pinboard. The main menu features only lists for viewing all bookmarks, unread bookmarks, and tags. Just tap one of these list items to view what it contains. If you are in the list of all (or just unread) bookmarks, tapping on one will open it in the app's browser. Bookmarks can also be swiped left upon to reveal action buttons, which present the options to delete, view in Safari, view using Instapaper's mobilizer, share, and edit the details of it. Also, unlike some other apps, Pinline provides the option to add bookmarks within the app by tapping the “+” button from the main menu. Yes, I'm looking at both of you, Pincase and Pinswift.
The other Pinboard clients that I mentioned are packed with social features, since Pinboard can be used as a social network for discovery. These are nice features once you get to try and use them, especially if you allow the public to view your bookmarks. On the other hand, for someone like me who uses Pinboard privately, and does not use any of the social features, these other clients are too complicated. For this reason, I will continue to use Pinline as my iPhone's portal to Pinboard.
If you would like a simple way to keep track of bookmarks on your iPhone, I highly recommend Pinline. It provides only the essentials, while doing so through an extremely basic user interface. I also recommend signing up for the Pinboard bookmarking service, which the app requires. Not only does it store unlimited bookmarks in the cloud for any-time access, but it does so while only asking for that cheap one-time signup fee.