Who tweets isn't as important as what they tweet.
Sometimes, an idea sweeps Twitter, touching the conversation of millions of people. Many other times, ideas disappear almost as soon as they appear. Researchers at the social computing lab at HP Labs in Palo Alto and Stanford University recently wrote a paperanalyzing what makes gives a topic on Twitter lasting popularity.
Twitter tracks these subjects of conversation in a "trending topics" list, and the researchers collected this data every 20 minutes for 40 days. They also collected tweets mentioning these topics every 20 minutes. They put the data together and studied it to draw conclusions about what makes a topic last.
Most trending topics disappear again fairly quickly, the researchers found, fizzling out within 20 to 40 minutes. Some, however, last for days.