Must See 99!

Twittercal
Twittercal is a service that connects your Twitter account to your Google Calendar and lets you add events easily, directly from your Twitter account.

Twitpay
TwitPay is a simple way to send payments via Twitter.

Twibs
Find, follow and interact with businesses, apps and services on Twitter.

Twittermail.com
Users can post to their Twitter account by sending a message to their own unique email address.

Twitzu
Promote your business, special offers, promotions and events with Twitzu.

Twuffer
Twuffer allows the Twitter user to compose a list of future tweets and schedule their release.

TweetLater
This app allows you to post Tweets at a later time and date.

GroupTweet
Send private Twitter messages to specific groups of friends.

Twitter Alerts
Keep track of conversations that mention you, your products, your company and anything else, via hourly email updates.

TwitPic
TwitPic lets you share photos on Twitter. You can post pictures to TwitPic from your phone, the TwitPic home page or your Twitter account.

Your Twitter Karma
Twitter needs a decent page for your followers, with the functionality to sort them by type. This Web app does that.

Mr. Tweet
A personal networking assistant for Twitter, helping you identify relevant followers, recommending you to other users and regularly computing your Twitter usage statistics.

Remember The Milk
Remember The Milk keeps track of your tasks. Simply add Remember The Milk as your friend, and you can add and interact with your tasks through direct messages and get reminders, too.

StrawPollnow
StrawPoll is the coolest way to follow the opinions of people on Twitter. With this app, you can create your own poll.

Twiddict
If Twitter goes down and you start to feel withdrawal symptoms, use this service to continue using it. Twiddict makes sure all your tweets end up going to the proper place.

Twitter Friends Network Browser
Browse through your Twitter friends, your friends’ friends, your friends’ friends’ friends…

Twitterfeed
Post your RSS feed to Twitter automatically.

Twitturly
Twitturly is a service for tracking what URLs people are talking about, as they talk about them, on Twitter.

Twittonary
The Twitter Dictionary, aka Twittonary, provides explanations of various Twitter-related words.

twtQpon
Enhance your social media marketing by offering discount coupons to the Twitter-sphere!

twenglish
Twitter translator: Simply type in your tweet, and twenglish will twanslate your tweet for you.

twtcard
Send a greeting card, a surprise message or an invitation on Twitter.

Tweet What You Spend
Cash-tracking made simple with Twitter.

Twittertise
Twittertise allows you to advertise on Twitter and track the success of your branded communications with customers.

TwitWall
With TwitWall, you can embed your favorite videos and widgets and upload your photos, MP3 music, podcasts, you name it.

UnTweeps
Unfollow Tweeps who have not posted tweets recently.

TwitRand
Select a random Twitter follower, friend or retweeter.

TwitBlocker
If you become overwhelmed by a Twitter user’s constant tweets, you can keep them quiet with a single click of a button.

Twitterless
Twitterless tells you who stops following you and graphs your follower history over time, displaying the info in a variety of useful views.

Twonvert
With Twonvert, you can easily convert your tweets into SMS shorthand language and say more with less characters.

Postica
Create a sticky note for your tweets.

twi8r
Translate from English to text message shorthand and vice versa.

Twitterholic.com
This website is constantly being updated to allow you to find the most popular Twitter users. Want to be on the list? Twitter constantly.

TweetStats
An app that tracks your number of tweets per hour and per month. It basically creates a graph based on your tweets.

Twitter Grader
Twitter Grader measures the power of your Twitter profile. How high do you rank?

twInfluence
Similar to Twitter Grader, twInfluence lets you calculate the indirect influence of you and your followers on Twitter.

TwitterCounter
A thorough analytical Web app.

tweetVolume
Enter keywords or a phrase and see how often it appears on Twitter.

Twist
See trends on Twitter; find out what’s hot and what people are saying about

TweetRush
TweetRush provides estimated statistics on Twitter usage over a period of time.

Tweetwasters
Just how much time do you spend on Twitter? Are you wasting time?

TwitterTroll.com
TwitterTroll.com is a real-time Twitter search engine to find new friends.

Just Tweet It
Just Tweet It makes it easier for tweeters to find other tweeters with similar interests.

Friend or Follow
Who are you following who is not following you back?

Qwitter: Catching Twitter quitters
Qwitter emails you when someone stops following you on Twitter.

Twubble
Twubble is a Twitter extension that helps you find more friends.

Twitter Follower-Friend Ratio
Your Twitter ratio is the ratio of your followers to friends (i.e. people you follow). It is measured with the TFF ratio (Twitter follower to friend ratio). The higher the ratio, the more Twitter heat you pack.

Nearby Tweets
Who is tweeting close to you? This app helps you connect with them.

WhosTalkin
WhosTalkin is a tool that allows users to search for conversations on the topics they care about most.

Twitter Search
Search Twitter is an excellent search engine that allows you to find out what’s happening in the world beyond your personal timeline.

Flaptor Twitter Search
Comprehensive Twitter search.

Twitscoop
Input a Twitter username or keywords in the Twitscoop search box to track a conversation, topic or conference.

Twellow
With Twellow, you can search for someone on Twitter or browse through various tweet categories.

twitSeeker
twitSeeker is an alternate search engine for finding Twitter users and browsing the results in one interface.

Hahlo
Hahlo is an excellent and fully featured Twitter client for your iPhone and iPod Touch.

TwitterFone
Send messages to Twitter using your voice.

PocketTweets
PocketTweets is a Web-based Twitter client for the Apple iPhone.

TinyTwitter
TinyTwitter works on any Java-enabled device and any Windows Mobile Pocket PC or smartphone.

TwitterBerry
TwitterBerry is a mobile client for posting updates to Twitter from your BlackBerry.

twitxr
Share pictures and status updates from your mobile.

Slandr
Slandr delivers an enhanced mobile website for Twitter.

Twitter2Go
Twitter2Go provides a quick and simple way to update your Twitter status.

Tapulous
Discover, connect with and send messages to people nearby. Upload photos and update your Twitter account.

Twittelator
Twittelator is an all-around great new application for your iPhone.

TwitterFon
TwitterFon is a simple, clean, easy to use and super-fast Twitter client for your iPhone and iPod Touch.

iTweet 2
iTweet 2 has built-in auto-refresh, search and hash tags. You can view user bios and locations and also view conversations with the “in reply to” links.

GPS Twit
Run GPS Twit on your phone to make it easy for your friends to find you.

iTwtr
An open-source Twitter client for your iPhone.

Twitter for WordPress
Twitter for WordPress displays yours latest tweets in your WordPress blog.

Twitter Tools
This plug-in integrates your WordPress blog and Twitter account. Pull your tweets into your blog, and create new tweets from blog posts from within WordPress.

Twitpress
Twitpress is a WordPress plug-in that submits a user-definable tweet to your Twitter account, notifying Twitter followers or friends that you have posted a new blog entry.

SimpleTwitter
SimpleTwitter allows you to add Twitter messages to WordPress templates (and not just in the sidebar).

Tweet This
A plug-in that adds a Twitter link to every post and page on your WordPress website, so that visitors can share your blog entries through their Twitter accounts. It also shortens URLs automatically.

TweetBacks
This plug-in imports any tweets that discuss your blog or post. The tweets appear as comments.

TwitterCounter
Install TwitterCounter on your blog to display the number of followers you have on Twitter.

MyTwitter
MyTwitter allows you to display your Tweets on your WordPress website and update your status on the MyTwitter settings page.

TweetRoll
With the TweetRoll widget, you can display the number of your followers and friends.

Twitt-Twoo
Twitt-Twoo is a simple little plug-in that allows you to update your Twitter status right from your blog’s sidebar.

Toro for Twitter
Designed to be simple, Toro uses an experimental Twitter client library to remove the Twitter API limit.

twhirl
Most of the features available on the Twitter website are accessible through twhirl, with usability enhancements.

Tweetr
Tweetr is a Twitter client that allows you to send and receive Twitter messages, but with some added cool features: support for taking photos with your webcam and sending files (up to 10 MB).

TweetDeck
TweetDeck aims to improve the existing functionality of Twitter by taking the abundance of Twitter feeds and breaking it down into more manageable bite-sized pieces.

DestroyTwitter
DestroyTwitter is a series of canvases that constantly update to keep tweets current and up to date using notifications that appear as soon as a new tweet is posted.

TwitterLocal
TwitterLocal is an Adobe AIR-based app that allows you to filter tweets by location.

Spaz
Spaz is a well-designed and well-developed Twitter client.

Snitter
Short for “Snooks’ Twitter,” Snitter is a cross-platform desktop Twitter client.

Twitch
Some features of Twitch are TwitPic integration, URL shortening, the ability to combine friends and replies, reply-highlighting hash-tag support and more. Firefox Twitter Extensions

TwitBin
TwitBin is a Firefox extension that allows you to keep up with all of your Twitter conversations directly from your browser’s sidebar. Send and receive messages, share links and more.

Power Twitter
Power Twitter adds a multitude of features to the Twitter website interface.

TwitterFox
This extension adds a tiny icon to the status bar that notifies you when your friends have updated their Twitter status. It also has a small text input field to allow you to update your own status.

Twitzer
This Firefox extension lets you post tweets longer than 140 characters on Twitter.

TwitterBar
TwitterBar allows you to post to Twitter from the Firefox address bar.

Twitter Search
This plug-in gives you quick access to the real-time Twitter search engine.

Hoopla!
An essential Twitter plug-in for the Firefox quick search feature.

TwitterEyes
TwitterEyes keeps track of your character count as you compose tweets and replaces characters if you need extra room. Finally, Worth A Look

Is Twitter Down?
Is Twitter down just for me or for everyone? This great app gives you a simple answer: yes or no.

twistori
An interesting Twitter experiment: click on a keyword on the left, and see what tweets are currently being published that contain that word.

Twittervision
A real-time geographic visualization of tweets. Amazing.

twittearth
Similar to Twittervision (above) but with a sleeker interface.