I'm not sure if this is the right community for this kind of question, but here goes.

When I browse the web, here is what I do:

* I always use [uBlock](https://github.com/gorhill/uBlock)
* I usually use [Self-Destructing Cookies](https://addons.mozilla.org/en-US/firefox/addon/self-destructing-cookies/?src=api) to delete residual cookies from YouTube, Amazon, etc. after I log out.
* I use [HTTPS Everywhere](https://www.eff.org/Https-Everywhere) to protect against eavesdropping on public networks.
* Flash is disabled whenever it is not in use
* If I'm looking something up quickly on a public computer, I use private browsing mode so that form entries are not logged.
* I carry a USB stick that has a portable version of Firefox with the above addons installed.

Do these tools (ad blocking, deleting cookies) actually do anything to protect my privacy, or do they give a false sense of security?

I am aware that Google, Facebook, etc. track my activity regardless of what I do on my local system. However, since their ads never actually reach me (meaning that I never click on ads), wouldn't this information be useless to them?