Here's an extreme example of how no-one - not even a fairly heavy-handed government - can keep people from talking about what matters to them.
As you probably know, the Mubarak administration have shut off internet access for the whole country, in response to widespread protests and civil disobedience in Cairo and other cities.
Now, a team of developers have cooked up a way for callers using ordinary phones to get messages out to Twitter.
Granted the messages all go via one account, and are thus pretty much anonymized, but the point is - you can't silence people forever, no matter how much control you think you have.
We worked with a small team of engineers from Twitter, Google and SayNow, a company we acquired last week, to make this idea a reality. It’s already live and anyone can tweet by simply leaving a voicemail on one of these international phone numbers (+16504194196 or +390662207294 or +97316199855) and the service will instantly tweet the message using the hashtag #egypt. No Internet connection is required. People can listen to the messages by dialing the same phone numbers or going to twitter.com/speak2tweet.
(Image: Egyptian pay phone, a Creative Commons Attribution (2.0) image from s_w_ellis's photostream)