About Direct Messaging:
This message would go directly to me and to no one else. Most people have their twitter accounts set up to automatically send messages to their email accounts. So, if you have your phone handy and you want to send someone an email very quickly, just DM them at Twitter.
About Retweeting (RT):
If you see a tweet that you really like and you want to send it to all the people who are following you, you can either click on the RT button, or copy their tweet, open your own message window, type RT in that window and then paste in their message.
The Best Time to Tweet:
The best time to tweet in order for your tweets to get noticed by the people who are following you is around noon, east coast time. Tweets keep coming, you see, and the stream on one’s Twitter home page just keeps flowing, getting longer and longer. Incoming messages flow on top of the older ones, and soon the older messages get buried by a huge stack, and your followers don’t bother scrolling down to see them. Therefore, it’s best to tweet when people are likely to be looking at their Twitter stream and see your tweet flowing in. For lots of people, that’s before an office work day gets rolling , say, between 8:00 to 9:30 a.m., and during their lunch hour, noon to 1:00, and before dinner, say 5:00 to 6:00 p.m.. If an east coaster tweets at noon, his tweets are likely to get noticed by California followers before work, by east coast followers on their lunch break, and maybe by European followers who are stylish late diners.
But, if you want to make sure your tweet gets seen by a follower, DM him or her (see first tip). This puts the tweet into his/her email inbox. It won’t get buried a stack (except maybe a very deep email stack!)