Imagine you're a professional and you tell someone you don't have a cell phone.
In most cases, people will be surprised (a few will be envious). Cell phones are almost expected right now. They're normal. They're even more normal for anyone tha drives in front of me on the freeway apparently.
As noted last week, smartphones were starting to become a social norm. Texting is rampant (even without Twitter). If I don't respond to text messages in an our or two people actually get worried.
Our technical usage has changed social expectations. What it means to be mature, connected, and even polite has been altered by the technologies we have.