In traditional Holiday Fashion I've elected to share with you 12 very clever, cool, and useful Twitter Third-Party Add-ons. These apps will definitely help you be more productive with Twitter, make your Twittering more enjoyable, and help to solidify your position as your company's resident Twitter Guru! Enjoy... as an added bonus I've also listed a few of the twitter tools that I have in my goody bag as well as a list of mobile Twitter clients.

 TwitterGroups
Twitter is way cool but once your network starts to grow at an exponential rate you may get a bit overwhelmed.. enter TwitterGroups. This tool enables you to create your own group (perhaps a group of several colleagues, a sports team, or maybe a project team). Create the group, invite members and voila... no worries about all your tweets being shared amongst all your professional connections, personal contacts etc... Want to meet people that share a common interest with you? Easy, search for a group and join up with others who share a common interest (photography, social media, heck, even GIS!) TwitterGroups is a great way to meet people that share a common interest enabling you to then "friend" them and follow them via Twitter as well, resulting in some great additions to your Twitter following.

 
 
TwitterFeed
Feed your Twitter account with your RSS feeds. This is a very popular and powerful add-on, particularly useful for a corporate Twitter account. Account setup is simple where you link a twitter account with an RSS feed then login via OpenID. Then, when your feed updates, the update will get pushed to the twitter account of choice. Note that your "tweets" will be followed up with a "Twitterfeed" suffix so all your followers will know that this is being pushed via RSS (i.e.. no human intervention). Many companies and news outlets (like @gisuser, @lbszone, @esri) use this to simply push updates to Twitter. Most accounts using Twitterfeed will have many followers and 0 or very few people that they follow.
 
Twellow
This is one of those really cool add-ons that you'll hit and then ask yourself, "why didn't I know about this long ago"? Twellow is a vast search utility enabling you to search Twitter for people by geographic location or by category. A simple search for "Fort Collins" returns a large listing of Twitter people that are in Fort Collins or maybe interested in Fort Collins. An advanced search on the term "ESRI" returns a decent list of people that are interested in the company ESRI. Finally, you can easily search people by industry or category as well. Want to find Bloggers that are on twitter... easy. The search on that category returns a list appearing in order of popularity (Scoble, Brogan, Cashmore, Rowse etc...) very interesting! Twellow comes from the developers of WebProNews

 
Brightkit
If you own or manage several Twitter profiles (for example, I have @gletham, @gisuser, @lbszone, and @symbianone) then Brightkit is for you as it does an amazing job to help consolidate all your Twitter accounts in one handy place. From the dashboard you can send a new tweet, browse replies sent to you etc.. all without having to login in and out of your various user profiles... handy!

 
TwitterTise
I think if you held a gun to my head and asked me to pick my #1 add-on then this would likely be it! You might think twitter advertising by the name but really, TwitterTise is much more than that! Using the application you login via your Twitter login pair, then you can schedule a tweet (setup a date and time to tweet - perhaps because you'll be away or maybe just sleeping!), then you're Tweet will appear at that time, with the click through url shortened for you (think TinyURL) and best of all, activity on your tweet will be monitored and you'll receive an email and Tweet telling you how many clicks have been made on your Tweet... wow!

 
SpinVox
Not to be outdone, an amazing provider of voice to text applications/services including voice to Twitter is SpinVox. Using the UK company's solutions, Twitter users can use their SpinVox account to speak a tweet or memo, then upload directly to Twitter. Spinvox also integrates with other social networks (facebook, Jaiku) and can also be integrated into a user's Ping.fm account. you can get more info by following @spinvox or follow their social media evangelist James Whatley @whatleydude
 
Twitbacks
Ok, here's the scenario... you've been Tweeting for some time now but you aren't too happy with the way you're Twitter page appears.. enter TwitBacks! this online service enables users to easily and quickly create a custom Twitter background - for free! Select a pre-defined theme (maybe a Christmas/Holiday), add your logo and/or image, provide some additional details, and best of all, add a few links to your other social bookmarks (LinkedIn, facebook, flickr, mySpace etc...) then save and upload via your Twitter design preferences. Simple, fun, and useful! you ca follow them @twitbacks

 
TwitterHolic
Indeed, maybe I am a TwitterHolic, but exactly what kind of history do I have?? Enter TwitterHolic. using this application users can see historical trends in their Twitter account. A graph is provided, showing the rate that followers have jumped on board. A tabular list them shows number of followers, friends, and tweets by date. A convenient list of other similar Twitter users (by location or interest) is also provided. Finally, you can use the application to tweet your stats!

 
TwitterCounter
This clever application monitors your Twitter activity, displaying a graph of your Twitter followers by week or month. Easily step back to see how many followers you've added over the past several months. The application also interpolates for you and predicts how many followers you "should" have tomorrow and next month! Registered users can also grab the code for a handy widget to share your twitter count with visitors to your blog or website.

 
TweetStats
For another clever application to view graphs of your twitter trends I suggest you also look at TweetStats - http://tweetstats.com/. Simply enter your twitter username, wait for the graph to appear, then browse your accounts follower history. This app goes way deeper than simply graphing your followers as it also provides details graphs showing patterns of your Twitter usage. For example, I tweeted more in October than any month this year, with most activity between 9-11 AM with Wednesday being my most active day and Sunday the least active!

 
TwitterFon
Here in North America there's a TON of iPhone users and naturally, iPhone users want to be connected to their Twitter.. enter TwitterFon. Its a simple, fast, and easy to use client for iPhone and has a really nice UI. Best of all, the App is free, available via the App Store - you can follow then on Twitter @TwitterFon
 
Other iPhone Twitter clients include:
http://www.atebits.com/software/tweetie/
http://twitterforiphone.com/
http://m.twitter.com/
http://pockettweets.com/
http://hahlo.com/
 
TwitterFone
Not to be confused with the previous entry, TwitterFone is a fun voice to text application (think SpinVox) enabling Twitter users to send a Tweet via voice call. Simply call your number, speak a tweet, wait a bit and your Tweet will be automatically converted to text and posted on Twitter. Interesting though that they haven't registered @twitterfone!
 
BONUS... Several other Twitter must-investigate apps (all in my toolbox) include:

• Twhirl - http://www.twhirl.org/
• TweetDeck http://www.tweetdeck.com/
• BrightKite - http://brightkite.com/
• Ping.FM - http://www.ping.fm/
• Slandr Mobile Twitter Client - http://m.slandr.net/
• Dabr Mobile Twitter Client - http://dabr.co.uk/
• Media on Twitter - http://mediaontwitter.pbwiki.com/ a Wiki of Journalists on Twitter
• pr140.com - awesome app for creating short urls
  

 
Some crazy stuff on Twitter:
Kikcbee - fetal kick detector that tweets when the baby kicks!

Happy holidays! from @gletham / @gisuser

See also Is Your GIS/Geo Technology Company Really Taking Advantage of Twitter and the Latest in Social Media