Behavioral advertising is online advertising based on your history of online activity. For example, if you visit an online shoe vendor, as you travel around the Internet, you might notice ads from that vendor appearing on unrelated, third party sites. This “trick” is accomplished by small cookie files that are stored on your computer by your browser. To opt-out of behavioral advertising (often called “remarketing”) the National Advertising Initiative provides a resource where you can see which advertising networks have placed cookies on your computer, and gives you the opportunity to opt out of seeing any more targeted ads from those ad networks.

In a recent announcement, Facebook has made the default privacy setting for status updates visible to “everyone.” What this means is everyone on the Internet, not everyone of your friends. The reason behind the change is Facebook’s desire to increase it’s visibility in search engines and to compete more directly with Twitter (where public updates are also the default setting.) It’s not hard to keep your old settings, but there is a lot of confusion about their interface and what the term “Old Settings” really means. Learn more at ReadWriteWeb.com .

Attention Hotmail and MSN users: itt’s time to change your password. According to Neowin, an anonymous hacker posted thousands of Microsoft’s Windows Live Hotmail usernames and passwords. The first list of over 10,000 accounts only includes account names that start with the letters A and B, but there was a hint that there could be more lists.

Although technically neither spam nor phishing, those aggressive emails from Tagged claiming a friend has sent you photos are certainly pushing the limits of netiquette. Ask Leo explains how Tagged.com got your email address and know your friend’s name, and why you should simply ignore them.

Your IP address is the logical identification (as opposed to a physical address) of your Internet-connected computer or router. It is a number formatted into 4 octets (or words) separated by periods, such as 184.238.14.180. Your IP address is shared with every website you visit, and frequently included in every email you send. But exactly how much can be learned from that IP address? Usually just your Internet Service Provider, and a general idea of where you are geographically. Your ISP, however, probably has records that tie you to your IP address. To learn more, read Bob Rankin on Does My IP Address Reveal My Location?.

According to an Information Week survey of 4500 computer security professionals, 22% of security breaches were done with “guessed passwords.” This means that the number one thing you can do to improve your security is to use passwords that can not be guessed. For starters, never use any word that appears in your account data, and never use a word that appears in a dictionary. For more password do’s and dont’s, read George Shaffer’s Password Basics).

OnGuardOnline.gov is a federal website with practical tips on securing your computer and guarding against Internet fraud. Information is delivered with videos, tutorials, and games designed to test and expand your knowledge. Topics include laptop security, social networking, malware, identity theft and much more.

Two ways to keep your browser’s search history private are to turn off auto-complete (also called auto-fill) and to clear your search history. Google provides step-by-step instructions for three popular browsers, and Leo Notenboom tackles the problem with plenty of screenshots.

To password protect a Microsoft Word document or Excel spreadsheet, go to Tools/Options/Security. Enter your password twice, and the next time you open your file, you
will be prompted for your password. This is helpful if you document is sensitive (such as a list of passwords), if you computer is shared by multiple people, or you want to email a private file.

The best defense against spoof (fake or phishing) emails is to be educated and informed about how to spot them. eBay has a good tutorial on how to protect yourself, as does Stop-Phishing.com from the University of Indiana. Number one tip: when visiting a site in response to an email that asks for some web action, do not click on the link in the email. Instead, navigate to the company site independently, either by looking it up in a search engine, or getting the URL off a billing statement.