Many studies have found that the following trends are apparent.
* Monday through Friday are the most active days.
* Most active time is about 11 am to 3 pm EST
* Mobile devices being the more popular tool
* TweetDeck, TwitterFon and Twitterfeed being popular non-Twitter publishing tools.
For more information, follow this link.
https://www.sysomos.com/docs/Inside-Twitter-BySysomos.pdf