This document discusses various apps and tools that can enhance the use of Twitter as a professional development (PD) tool. It describes Twitter's core features of short text posts and real-time updates. It then summarizes several apps including Twibes for finding others with similar interests, Tagdef for understanding hashtags, TweetedTimes for organizing tweets into newspapers, Scribd for sharing documents, GroupTweet for private group tweeting, Twitcam for live streaming, and Spezify for visual hashtag searches. The document advocates using Twitter for teaching and learning through communities, resources sharing, and interacting with experts. It provides tips for maximizing tweet impact and lists review questions about the summarized tools.