Twitter rescheduled an upgrade because protesters in Iran were reliant on the microblogging website to share information.
Following the disputed election at the weekend the Iranian government blocked the use of social media applications such as Facebook and YouTube but forgot about Twitter, according to Fox News.
People in Iran have been able to communicate with the rest of the world as a result.
Twitter changed its plans for putting the website down as a result.
"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 recognise 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)," said Twitter in a statement.