Non traditional helpdesk systems
Helpdesk software market has been around for several decades. And the feature set most systems offer has become pretty standard: most systems track case-history, allow file-attachments, automation, collision detection, knowledge-base etc. etc. The workflow is pretty common as well: a customer files a support request (via email in most cases) and the team answers this request using a helpdesk app. Sometimes delegating the "case" to other team members, attaching files, using "canned reponses" and tracking the customer's previous history of tickets.
But some systems try to do something new and offer a different workflow. They weren't able to change the way customer support industry works, but they sure found their way to get a slice of this market.
Get Satisfaction is basically a public forum, where users reports bugs and feature requests. Then these bugs get "voted" up and down by other users. And finally, when a bug or feature requests gets enough of these "me too" votes - the company steps in and "handles" the case. Sounds very interesting unless you actually don't want to be open about your products issues. Fits great the open-surce projects though.
UserVoice is pretty similar to GetSatisfaction. It is also a public community support platform where users "vote" and help each other out. But the company has decided to move to a traditional helpdek market since, shifting the feature set towards a traditional "helpdesky" one. They still offer the original product as "UserVoice Feedback" though.
Intercom is a very interesting product. It is an in-app messaging platform that offers a semi-automated way of contacting your customers right within your app. Sometimes - automatically, when a user triggers some action. It's an "outbound" support system, but it also offers a way for the customer to contact the company as well. The product is very intriguing, cause is does not just offer a way to get feedback efficiently, but also drives your conversions and fights the "churn" (cancelling customers) by contacting users where they probably need most help.