A Community Knowledge Worker (CKW) is essentially an ICT enabled agricultural extension worker. Using a high capability mobile phone and cutting edge mobile applications, the Community Knowledge Worker delivers expert approved information to farmers and pushes farm level data and observations back to the experts or other agricultural players.
Farmers who become CKWs are so nominated by farmer associations or extension organizations working in their areas, they are vetted by Grameen Foundation for their potential as information service providers and voted for by the farmers in the areas they are meant to serve.
Upon being recruited, CKWs are rigorously trained on both mobile information dissemination and collection. On average, every CKW, undergoes eight full days of training over a one month's period.
Training includes introduction to the program, its principles, expectations of CKWs, and goals for improving effective services to farmers. It also covers use of the mobile phones, how to provide mobile information services, quality control and survey methodologies and how to conduct mobile data collection. The training are highly practical. 
See copies of CKW training manuals:
Introduction to CKW Program and Mobile Phone Use
How to Provide Mobile Information Services
How to Conduct Mobile Data Collection
CKW Skills
Information Dissemination: CKWs can manipulate our cutting edge applications to  disseminate information to farmers on any range of topics including specific crops, market information like prices, directories of traders, location of markets etc. In addition, they collect profile and location information of users which each query.
Data Collection: CKWs use sophisticated mobile data collection tools to collect multimedia farm data in any given agricultural domain. They have worked with leading agricultural extension organizations like the World Food Program and the International Institute of Tropical Agriculture to collect agricultural surveys on areas such as; plant diseases incidence, small holder farmers� potential to supply to markets, adoption of expert advised techniques such as fertilizer use etc.
Survey products can be selected according to packages, or customized to customer needs based on type, length, frequency, and other variables. A list of standard packages can be found here.