For most Web activities, many people won't be bothered that they are served up ads for cars or even acne cream if they have been reading news about the newest Tesla or visiting dermatology Web sites. But what about when someone is researching a hereditary or embarrassing medical condition that one would not want revealed to advertisers, shoulder surfers or, worse yet, insurance companies?

Private Mode

You might want to start by perusing the Web in Private Mode. Private browsing, affectionately dubbed "porn mode," allows you flip a switch in the browser so it stops saving a record of the sites you have visited and content you have downloaded until you flip the switch off.

• In Firefox it's called "Private Browsing."
• There's an Incognito mode extension for Chrome.
• Internet Explorer has an InPrivate browsing feature, which offers a way for people to selectively block sites from tracking.
• Apple has had private browsing since OS X Lion.

Do Not Track

Not only have researchers figured out ways to defeat some of the private browsing features, but private browsing offers limited protection. For example, private browsing tools don't stop social sharing buttons and ads from following you as you bounce from site to site.

As a result, software like Abine's Do Not Track Plus browser add-on, blocks Web sites and ad networks from following you around the Web and lets you see who is trying to track you.

And there is AVG's Do Not Track, which lets you fine-tune the blocking of ad networks and Web analytics.

IP masking

Cookie disablers block the storing of cookie data on your computer, so your browsing history can't be recovered later from the machine. But they do nothing to prevent Web sites you visit from grabbing your IP address and correlating that data with other information the site may have on you or your account. Governments regularly ask ISPs for user data as part of investigations and this can lead to real names and addresses. Even though Web browsing is logged according to the customer's IP address, which identifies the computer used, the ISP can easily associate IP addresses with subscribers who are required to provide personally identifiable information for payment purposes.

The latest version of HotSpot Shield from AnchorFree hides the IP address of Web surfers and blocks ad tracking. It operates like a virtual private network, transmitting data over encrypted connections through its servers to hide the IP address. This has the added benefit of protecting users against wifi spoofing or man-in-the-middle attacks.

Anonymous browsing

And for the truly hard core, there's the Tor Project, which operates a network that offers anonymous browsing over encrypted channels. But it may be overkill if you are mostly interested in staying out of sight of ads.

Got any other tips or suggestions? Let us know