A critical network upgrade must be performed to ensure continued operation of Twitter. In coordination with Twitter, our network host had planned this upgrade for tonight. However, our network partners at NTT America recognize the role Twitter is currently playing as an important communication tool in Iran. Tonight's planned maintenance has been rescheduled to tomorrow between 2-3p PST (1:30a in Iran).
As I explained earlier, Twitter has been a lifeline for Iranian protesters, to get news out of Iran when the Iranian Government has been trying to block their access to the outside world.
Postponing a major upgrade for a service that size is not a decision made lightly, nor without risk, but their decision to do so to keep lines of communication open between Iranians and the world, is a good one.
You can keep up with the news coming straight out of Iran at Twitter, search term #IranElection, found here.