riffle - a browser plugin which gives you vast insights into any Twitter user you choose. Discover statistics, popular hashtags, most shared links, connected profiles, and much more. twitemail.com- Twitemail is the easiest way to share emails on Twitter.
twtbase.com - Twitter application database. Every app you can think of for Twiiter such as the:
Tweeting Machine (for automating the usage of Twitter. It has 6 main features: schedule tweets, create queues....).
Twit Desktop (share your desktop screenshots with others on Twitter. You can check last shared desktop screenshot on the website with ratings.).
WWWitter - is a tool that lets you take part in Twitter discussions about any webpage. You can launch the WWWitter bookmarklet from any page on the web, and you don’t need a twitter account to read what people have been saying.
TweetBlocker - helps in identifying the spammers in your followers. It’s very simple, just provide a twitter username and TweetBlocker will check its tweets and rank the user with a grade from A to F. Or you can login and it will check all your followers for spam tweets. The application is pretty similar to TwitBlock app. The big advantage of using TweetBlocker is its ranking for the twitter users (A to F) rather than saying a twitter account is a spam or not as TwitBlock (which is not accurate all the time). Greet tool to block spam accounts.
moTweets - is popular and one of best Twitter apps for Windows Mobile devices. It provides many functionality like supporting multiple twitter accounts, upload pictures, and URL shortening. moTweets comes in two versions: free with ads, and not free for $3.99.
Peekr - Have you ever wanted to actually see the whole background image of someone’s profile on Twitter? Well, now you can with the Peekr bookmarklet. When you’re on someone’s Twitter page, all you have to do is click the bookmarklet and quickly see their whole background.
TwitDraw- The app is very simple to use. You can watch a replay of the drawing and choose the speed of the replay. It will ask for your twitter account to tweet your draw hashed with twitdraw. And your followers can rate your draw and may place at the top rated draws in the gallery.
mytoptweet.com- My Top Tweet lets you find the most tweeted tweets from any Twitter account!