In countries like India the internet penetration is low, especially in marginalized communities. It is still a long way for the rural poor to afford proper infrastructure and gain access to the internet. Organizations struggle to reach to these communities isolated geographically, and distanced by local languages. These people usually have low rate of literacy and have limited experience with information technology. However the mobile penetration is high and can be a deal breaker in ICT based development efforts.
Awaaz.de is an innovative software program (voice-XML based Interactive Voice Response system) that allows development organizations to connect with these poor, rural and marginalized communities by providing on-demand, many-to-many information access through mobile phones. People can access Awaaz.De applications by dialing regular phone numbers to work with voice contents through automated voice interfaces. When a farmer calls in, he/she hears audio prompts and is asked to enter a number from the keypad or say a word in order to navigate. Voice applications overcome the language barrier, offering services in local languages and overcome literacy constraints.
Awaaz.De was founded by  Neil Patel and Tapan Parikh two years ago. Their first effort was Avaaj Otalo , an open-source, voice-based platform for Gujarati farmers. According to Mobile Active's case study :
Avaaj Otalo provides three modes of functionality. When farmers call in, they can either listen to archives of DSC's weekly radio boradcast, listen to announcements from DSC staff put up specifically for Avaaj Otalo, or participate in the question-answer forum. The archive and announcements are offered for browsing.
According to Center Of Microfinance blog  “the project has the potential to go much beyond the purview of agriculture and have positive effects on farmers’ health status as they switch to pesticides which pose lesser health risks”.
And rightly so Awaaz.de is also using its voice message board and serving a number of development organization clients  across 6 states in India to conduct survey, campaign and other services for the. The services include phone surveys, broadcast messages to wide or targeted audiences, and track usage and reach clients with comprehensive reporting for them. All software are open source and offered as an end-to-end hosted service. Tapan Parikh explains in Ushahidi blog 
A web-based dashboard is used by community moderators to curate and categorize user submissions, facilitate sharing of knowledge and disseminate targeted information, while creating a home-grown database of users and local-language voice content. A more detailed description of how Awaaz.De works can be found here .
Here is a video featuring Neil Patel, who is explaining what Awaaz.de does.