The vast majority of the things that adware programs find are tracking cookies - at least this is my experience.
You can do a number of things, such as disable cookies or prompt to allow cookies in your browser.
However 1) will stop most sites from working and 2) will drive you mad.
Another approach is to block the domain on your firewall (e.g. block adbureau.net or tribalfusion.net etc.).
A similar effect can be gained by adding lines in your hosts file (that's c\windows\system32\drivers\etc\hosts) linking the server.domain name to the loopback address of your own PC.
However, this is limited to specific servers, rather than entire domains, so is much more tedious to populate - and maintain.
Another approach is to kill the cookies as they arrive, or on startup / shutdown with an adware program - though frequently you actually have to pay for this functionality.
SD