Even if you don't have your own account, Twitter has its uses. It's increasingly used by government agencies to communicate information, as demonstrated by a useful list of agencies that have taken to tweeting.
eGov AU has assembled a handy list of government Twitter accounts, available both on its site and as a Google spreadsheet. Not all the accounts are particularly active, but it's worth a scan if you're looking to expand the range of people you follow beyond friends, Lifehacker and Ashton Kutcher.
Australian government Twitter accounts [eGov AU]