Janetter - Janetter is a Twitter client application. Faster, smarter, and more powerful.
Wordpress Read Time - Shows you the reading time of your blog post as you write
Tweetbot - Sync your timeline across your iPhone, iPad, and Mac. Mute tweets by user, hashtag, tweet source, or keywords (including regex). 3rd Party support for image, video, read later, and timeline sync services.
How Long to Read - Find out how long will it take you to read that book
YoruFukurou - YoruFukurou (NightOwl) is a Twitter client for Mac OS X, designed for Twitter addicts.
The Read Time - Calculate read time, speech time, and word count of any piece of text all at once!