PGP, or Pretty Good Privacy, is a system that uses public/private keys as a means for encryption and message verification via signatures. By using the public key of your recipient, you can encrypt a message (or file) so that only the intended receiver can read the message. Also, by using your own private key, you can create a signature that cannot be faked, which serves as a means of authenticating a message and detecting forged messages.
After 30 days, Trial Software reverts to the functionality available in what used to be called PGP Freeware, or you can simply not enter the trial code and use the freeware functionality from the beginning.
The short answer is that the Hosts file is like an address book. When you type an address like www.yahoo.com into your browser, the Hosts file is consulted to see if you have the IP address for Yahoo. If you do, then your computer will "call it," and the site will open. If not, your computer will ask your ISP's (Internet service provider) DNS Server (domain name services) for the IP address before it can "call" that site. Most of the time, you do not have addresses in your "address book" because you have not put any there. Therefore, most of the time your computer asks for the IP address from your ISP to find sites.
If you put ad server names into your Hosts file with your own computer's IP address, your computer will try to connect to your own computer each time it's pointed to that ad server, and since there's no ad on your own computer, nothing is displayed, nor will any tracking take place.
Your choices for blocking sites are not just limited to blocking ad servers. You may block sites that serve advertisements, sites that serve objectionable content or any other site you choose to block.
You can read more about the Hosts file and how it works here. Download (eDexter or HostsToggle) to make browsing with the Hosts file smoother, faster and easier.
Here are two different Hosts files (updated frequently):
Ad-aware is a small and easy-to-use program that will scan your system for known adware/spyware and allows you to safely remove them from your system.
During the process, Ad-aware scans your memory, registry and file system for known modules. If a related module is found in your memory, it means the spyware was active until Ad-aware detected and unloaded the particular module.
A Web Bug is a graphic on a web page or in an email message that is designed to monitor who is reading the web page or email message. Web Bugs are typically only 1-by-1 pixel in size and are often invisible. They are represented as HTML IMG tags.
Below is an example of a Web Bug found on Quicken's website (www.quicken.com):
This is an excellent question and one that comes up in the Security Forum on a regular basis.
The endless list of new anti-spyware programs and utilities seems to grow each day, which can be confusing for everyone from new users to the experts who may have a hard time keeping up with that list.
Eric L. Howes, developer of IE-SPYAD, has compiled a marvelous "Rogue/Suspect" list for reference that is sure to help:
said by Eric L. Howes:Note: "Rogue/Suspect" means that these products are of unknown, questionable or dubious value as anti-spyware protection. Some of these products simply do not provide proven, reliable anti-spyware protection. Others may use unfair, deceptive, high-pressure sales tactics and false positives to scare up sales from gullible, confused users. A very few of these products are either associated with known distributors of spyware/adware or have been known to install spyware/adware themselves.