That means you shouldn't check your e-mail or any authenticated online service portal using a computer that is not your own. Don't use the hotel's computer. Don't use computers at conferences. Don't use your friend's computer. Don't use a co-worker's PC. The risk that the computer not under your control is exploited is too high, and once the bad guy has your log-on credentials, it's all too easy to mess with your digital life.
If you are involved in your company's computer security, you should make a new policy saying that no one should ever type their authentication log-on credentials into a nonmanaged computer. Make it a policy and enforce it. I know of one company that shut down its online, Web-based e-mail system until it could get a two-factor system enabled for all employees.
That's a good solution. Any security system that doesn't rely on a simple, one-factor, traditional username and password is better. While not perfectly secure, a two-factor system or something using a one-time password/PIN (such as a RSA keyfob) does provide additional security that would be sufficient to protect most online systems.
The risk of accessing your own personal system or corporate assets is just too great to be hoping that the system you are using isn't exploited. And increasingly in this world, that computer not under your control is infected. Just say no.
This story, "Don't trust a public PC with your digital identity," was originally published at InfoWorld.com. Follow the latest developments in security at InfoWorld.com.