This month, let's look at 10 applications that complement Twitter, enhancing its capacity to help you grow and operate your company. Thanks to Twitter's freely available API, there are piles upon piles of applications out there that integrate with it. Here are the ones I've found most intriguing.

Marketing tools
This first group are tools that will help you market to, and using Twitter.

#1 Twibs
Twibs is a directory to more than 10,000 businesses on Twitter. You can opt-in to have your business listed there. Listings include your business name, Twitter username, search tags to help people find you, email and other contact information, and more. You can also enter your street address and it will appear alongside your listing in a Google Maps widget.

Twibs -- a free service -- is no fly-by-night operation. You'll find companies ranging from CNN to Whole Foods there. There are a number of other Twitter directories out there, but for the time being, this seems to be the place for professionals to be.

#2 GroupTweet
GroupTweet is a Web-based tool that allows you to narrowly target a group of Twitter users with a direct message. This can be handy if, say, you have a special offer or unique content you only want to share with a handful of users.

It works both ways, too. Anyone within your circle of GroupTweet contacts can send a message to the rest of the group. GroupTweet essentially lets you create a private discussion group, within Twitter's environment, centered around your company and your customers.

The obvious negative here is you could get some mischief maker on there pestering your other customers. But, it appears the next version of GroupTweet might allow the group owner to moderate messages sent to the group. And the price is right: it's free.

#3 TweetBeep
TweetBeep is an alert service that notifies you every time someone on Twitter mentions your company, your products, or anything else you want to follow.

Upon setting up a free TweetBeep account, you can specify keywords you want to monitor. You can also narrow the focus to just Twitter users within a certain geographic area. Hourly email updates will allow you to monitor chatter about you and your company in near real-time. The power of TweetBeep as a market research tool is pretty obvious.