That is primarily because "tweets" may be answered immediately upon receipt or not, depending on the circumstances of the message recipient. Needless to say, there are countless imaginable situations where phone calls between individuals and (especially) among larger groups such as classes would be impractical for which "tweets" fill the role perfectly (Welch & Welch). The range of possible administrative and educational applications in the university setting is very broad; it includes many of the informational functions of the Internet without the same investment of attention as traditional Internet communications. Facebook and is also potentially extremely useful in many of the same ways and provides a trade-off of greatly increased full-function Internet capabilities at the expense of the immobility of desktop computers, the inconvenience of relying on a laptop being perpetually...

Ultimately, it is likely that Twitter and Facebook will revolutionize personal and professional communications in this decade as much as cellular phones and the introduction of Internet applications did in the previous decade.
References

Johnson, S. "How Twitter Will Change the Way We Live (in 140 characters or less),"

Time; Vol. 173, No. 23 (June 15, 2009): 32-37.

Welch, J., and Welch, S. "Why We Tweet." Business Week; June 15,…