Here's another hole for you to fill, Twitter. While users of the popular status message website can easily block spammy members, there's no way to find a list of accounts that you have blocked. No way, that is, except for through Twitter's own API.
The blocking request has been part of the API for at least a year. Yet it's never found its way on to Twitter.com. So, Q&A sites are filled with questions from Twitter users asking how to see their blocks. Several developers have exposed the list with mini apps.
Who I Block is one such app. Just authenticate with Twitter and it shows you a barebones list of those you have blocked. It could certainly be improved to help people find and unblock the friends they may have--GULP--accidentally blocked.
However, there's not much reason for a developer to spend much time on a feature that should probably be part of the site anyway. It is likely a hole that Twitter will fill eventually. Developer Damon Cortesi, who himself once wrote an app (now defunct) to show blocked users, thinks it's worth being wary of building something Twitter may build themselves. "They're obviously experimenting with a lot of different stuff and it's not clear what is going to stick," he said. Cortesi mentioned mutual friends and inline media, each of which has shown up for some Twitter.com users recently--and each of which has multiple apps written by developers to do the same thing.
Still, it's strange when Twitter implements something in the API but not on the site, right? Well, not really. Many features, such as geocoded tweets and retweets, have been built first for developers. Each was then rolled out to the main Twitter site within a few months. Cortesi points out annotations is another such feature. Announced at the Chirp developer conference, it is available only via the API and only to select developers.
Hat tip: Craig Fisk