Privacy on the web

When someone speaks about the privacy on the web, one means advertisers' activity to track your online movements, habits and preferences. This threatens your privacy and allows advertisers to supply you with more targeted ads. The primary mechanism to track your online activity is cookies.

Ad Annihilator has efficient and flexible means to block cookies (see What could I do to protect my privacy? to find out which).

What are cookies?

Cookie is actually just a small file stored on your hard drive. Cookie are associated with a specific web site and are created from visiting web sites that support cookies. They may contain information about your visit to the particular web site. The next time you visit that web site (or potentially some others), that data is accessed again!

Why cookies are bad?

The most pressing issue concerning cookies centers about concern for user privacy and the potential for abuse. Advertisers are using cookies to develop detailed profiles of people and their browsing habits. Each click on an advertisement or web page can be added to a profile maintained by the advertiser. 

For the time being this information is primarily used for the placement of banner advertisements, but the possibility exists that these profiles will be sold to other commercial interests. This could lead to deeper violations of personal privacy, because if an advertiser links a user identity to their cookie ID, then that information could also be resold. Once your identity becomes known to a single company listed in your cookies file, any of the others might know who you are every time you visit their sites.

Then why are cookies still needed?

While most people believe that most cookies are an invasion of privacy, some sites will only function if cookies are enable/allowed. Online shopping carts are a primary example of this; they use cookies to track customers while they shop. Cookies may be useful to keep, for example, the user name you use to login to an online service to supply this name automatically later. Unfortunately, this capability is abused by advertisers and they turn it into a powerful tracking mechanism.

Good news are Ad Annihilator offers powerful cookie blocking filters that allow you to differentiate between useful and bad cookies (see How to block cookies? to find out how to block cookies)

How do cookies work?

When you visit a site that supports cookies, the site sends to your computer a portion of information, say your user name, that is stored on your hard disk. Later when you access that site this portion of information is sent back to the server. Note that information is always sent back only to that server that sent it previously. On the first glance, it seems that this fact precludes advertisers from tracking your activity as advertisers get the same information they sent themselves earlier. However, there are two potential threats:

• When you return to the same site later, it may detect your previous visits;
• When you visit another site with advertisements from the banners site, the banner site will be aware of your identity and will update your profile.

In both cases your privacy is violated and advertisers are able to maintain your profile and supply you with more targeted advertisements.

Cookies types

Cookies could be categorized by two criteria: direction and cookie type.

As follows from the discussion of cookie operation above, cookies are both sent to your computer and sent from your computer. This fact allows differentiation of cookies by direction:

• Incoming cookies (cookies that are sent from the web server to your computer);
• Outgoing cookies (cookies that are sent from your computer back to the web server).

Outgoing cookies blocking prevents from sending of information from your computer to the web server. Incoming cookies blocking prevents reception of cookies from the web site so cookies are even not stored on your hard disk. If outgoing cookies are enabled and incoming are disabled, new cookies will not be accepted but previously stored cookies will be sent. However, if cookies from certain web site are not desirable, is recommended to block both incoming and outgoing cookies.

Following types of cookies could be distinguished:

• First-party persistent cookies;
• Third-party persistent cookies;
• Session (temporary) cookies.

A first-party cookie either originates on or is sent to the Web site you are currently viewing. These cookies are commonly used to store information, such as your preferences when visiting that site.

A third-party cookie either originates on or is sent to a Web site different from the one you are currently viewing. Third-party Web sites usually provide some content on the Web site you are viewing. For example, many sites use advertising from third-party Web sites and those third-party Web sites may use cookies. A common use for this type of cookie is to track your Web page use for advertising or other marketing purposes.

We referred to first- and third-party cookies as persistent cookies. A persistent cookie is one stored as a file on your computer, and it remains there when you close Internet Explorer. The cookie can be read by the Web site that created it when you visit that site again. First- and third-party cookies are sent only until a certain date that is reported by web servers. This date is called expiration date.

On contrary, a temporary or session cookie is stored only for your current browsing session, and is deleted from your computer when you close Internet Explorer. Note that both first- and third-party cookies could be temporary but for the purpose of cookie blocking it is sufficient to put them in a single "session cookies" group. Temporary cookies are often used to support shopping carts and other online services web sites. Session cookies have no expiration date, they expires when you close the browser.