Andy Dickinson has created a plugin for self-hosted WordPress blogs which allows you to add the functionality of Help Me Investigate.
The plugin follows the HMI structure of Investigations and Challenges. An investigation starts with someone asking a question. The questioner can then set a number of challenges to help them and the community answer the question and share the results.
You may, for example, ask What is the average cost of a pint of bitter?. A good challenge may be to ask participents in the investgation to find the price of bitter in their local pub. But you could also set a challenge to map the information and publish it on google maps.