Pew surveyed 2,253 Internet users, age 18 or older. A third of the respondents fell into the 18 to 29 age range. If you tack on the 30 to 49 age range you find that 55 percent of those who stay in touch via status update are under age 50.

The survey also found a correlation between the number of wireless devices a person owns and the likelihood that they also use a status update service like Twitter. Only 10 percent of users with one Internet-connected device claimed to use Twitter, while nearly 40 percent of those with four connected devices use status updates to communicate. In fact, there is essentially a 10 percent per device relationship, with two devices coming in at 19 percent, and three devices at 28 percent.

One thing to note is the qualifying statement throughout the report that it is a survey of those "who use Twitter or another status update service." Twitter is getting the attention from the survey, but based on the wording of the statement it seems that Facebook may make up a significant portion of the responses-- perhaps more than Twitter.

Facebook . Studies that Facebook has over 1 billion visits to its site each month to Twitter's roughly 55 million. Facebook users also do status updates-- more than 40 million of them per day. The combination of the massive membership of Facebook and the sheer volume of status updates on the social networking site would suggest that it falls within the scope of "Twitter or another status update service."

One thing that sets Twitter apart from Facebook though is the ability to send and receive status updates via SMS text messaging. Web-enabled mobile phones can access Facebook, Twitter, or other status update services. These services also provide apps for devices like the iPhone and Windows Mobile phones. But, Twitter stands alone in that tweets can be sent via text messaging, and users can designate specific users to have the tweets sent to their mobile phone via text messaging. The 140-character limitation of Twitter tweets lends itself well to text messaging.