Two weeks after TV star Ashton Kutcher had his Twitter account hijacked by critics of Twitter's security policy, while at the prestigious TED conference, Twitter just announced the addition of a new feature to every account: HTTPS by default.

Secure HTTPS connections to social networking sites are important on open public Wi-Fi networks but haven't been easy for users to set up until now. In its announcement this afternoon, Twitter said it hoped in the future to turn on HTTPS by default (really default default, in every case) not as a user option to select, automatically in all circumstances. This is very good news for its users and for Twitter's long-term viability.

As Twitter moves more and more towards mainstream and celebrity users (as opposed to technical power users) - making security and the integrity of identity really simple grows all the more important. If stars on Twitter regularly lost control over their own voice and brand like Kutcher did earlier this month - that would be very bad for Twitter's strategic interests.

"Use HTTPS by default" is now the last option on the Settings page for each account. It is wise for anyone who logs into Twitter in public to go and check off that box.