1. Twenty six percent of online adults discuss health information online; privacy cited as the biggest barrier to entry. http://www.businesswire.com/news/home/20121120005872/en Twenty six percent of online adults discuss health information online; privacy cited as the biggest barrier to entry. http://www.businesswire.com/news/home/20121120005872/en
2. Twitter blogs: measuring tweets. http://blog.twitter.com/2010/02/measuring-tweets.html. Twitter blogs: measuring tweets. http://blog.twitter.com/2010/02/measuring-tweets.html.
3. Twitter statistics. http://www.statisticbrain.com/twitter-statistics/ Twitter statistics. http://www.statisticbrain.com/twitter-statistics/
4. http://www.google.org/flutrends/us/#US http://www.google.org/flutrends/us/#US