6. Protect updates
By default, all Twitter users can find your updates through the search function or by browsing your profile. However, you can protect your updates so that only your followers and people you approve can see them. To do this, log in and choose 'Settings | Account', then tick 'Protect my updates' and 'Save'.
7. Be sensible
Protecting Twitter updates improves your privacy, but it greatly reduces your visibility. General users won't be able to find you if they're searching something that you've been tweeting about. An alternative is to be vigilant about what you post, ensuring that you don't include facts that reveal sensitive information.
8. Remove offending tweets
If someone else has posted your private information on Twitter, you can ask to have it removed. Submit a request at http://twitter.zendesk.com/requests/new, including all details of the privacy breach and links to the tweets in question. Twitter aims to respond within 24 hours.
10. Tighten LinkedIn privacy
LinkedIn has a professional focus, but there are still some ways to tighten your privacy on the network. Log in and choose 'Account & Settings | Profile Views'. Here you can control what information other people can see about you when you visit their profiles.
You can opt to show your name, but you can also display some anonymous statistics instead, or even hide the fact that you've viewed a profile. If you want to avoid sending notifications to all your connections when you edit your profile, choose 'Profile and Status Updates' and opt to not notify anyone of updates.
11. Tighten MySpace privacy
MySpace has a younger demographic than other social networks, and its focus is more towards socialising and artistic expression. To change privacy settings, log in and choose 'My Account | Privacy'.
You can opt to hide when you're online and to make your profile only visible to your friends. You can also restrict access to your profile from minors and prevent them from contacting you. The block list also enables you to block individual users.
12. Stop application access
MySpace has literally thousands of different applications available of variable trustworthiness. In 'My Account | Applications', block any apps that you don't trust.
You should also opt to block applications that you haven't added from viewing your display name or from contacting you.