I use Twitter but I am in the minority. Twitter will not be the next Facebook. It is all hype.
Only 17% of Twitter users are active according to RJ Metrics. That would make the Australian active audience for Twitter around 136,000. 80% of Twitter users have made less than 10 updates.
Even the tech hungry teens don't like it. According to Pew Research 8% of internet users aged 12-17 use Twitter. This makes Twitter as common among teens as visiting a virtual world, and far less common than sending or receiving text messages as 66% of teens do, or going online for news and political information, done by 62% of online teens.
Twitter is not the next Facebook. According to Neilsen In October, Australian users spent 27.2 hours browsing online and 7.55 hours of the total was sucked up by Facebook whereas Twitter accounted for 17 minutes. Twitter's active Australian user base is the equivalent of less than 2% of Facebook's Australia audience.