What questions should an encyclopedia of social media address?

One of the first assignments that our class is going to start working on is the creation of an encyclopedia of social media.  Each of us is going to create a video in Camtasia Studio or Adobe Premiere which will introduce the encyclopedia’s audience to an online community or social network.  And this begs the question--what questions will each entry in the encyclopedia need to answer about the social network or online community being addressed?  In other words, if the whole class is creating the encyclopedia together, what framework should we use to make sure that we're all addressing roughly the same issues?

To help us begin thinking about this, here are some questions I brainstormed as I was doing the Paul Gillen Secrets of Social Media Marketing and the Design to Thrive readings for class.  These are some of the questions that I thought someone reading an entry from an encyclopedia of social media would want to see discussed:

• What's the history of the service, and how long has it been around?
• What's the Alexa ranking of the site, or other measures of its success/popularity?
• How would you describe the services' basic functionality?  What kinds of "use cases" does it support?  What kinds of problems does it solve or questions does it answer? How do people connect?
• What would a tour of the site look like?  Does it have a GUI interface or what?  What's the user experience like?
• Who does the service support; i.e., what demographics mainly use it?
• How much does it cost, and how does someone register to use it?  Is it public and open, is it a subscription service, or is it exclusive and by-invitation-only?
• What business model does it use?  How is it monetized?
• What privacy protections, intellectual property protections, and EULA issues are operating on the service?
• How customizable is the service/interface and will it support corporate branding requirements?
• Assessiblity:  1) ease of use; 2) delivery/distribution systems, & 3) system requirements

These are just some of the questions we could address in our encyclopedia entries.  What are some others you think are important topics to consider?