Browser settings to prevent tracking
All modern browsers have a "Do Not Track" (DNT) option you can set. What it does is sending a specific header to a website, asking for you not to be tracked. However, the website might pay no attention to that and keep on tracking you anyway, even though it might result in non-compliance with the law.
For example, Firefox users may activate an embedded "Tracking Protection" feature. It should not break any sites (even though might render the stats for those sites less reliable), and it can be disabled on per-site basis if you like. With this feature on, 44% average reduction in page load time has been observed, as well as a 39% reduction in data usage.
Plugins and extensions to prevent tracking
You might also want to use some additional tools to prevent excessive tracking. For example, have a look at uBlock Origin or Privacy Badger (from the guys at Electronic Frontier Foundation). If you want not only to block tracking, but also block the scripts and some other embedded elements which might be potentially unsafe or just plain annoying, check out NoScript.
Please note that removing the scripts may render some sites non-functional. Also don't forget to check the default settings for those extensions and review the default whitelist in NoScript.
Finally, to automatically switch to a secure connection to the site whenever possible, install HTTPS Everywhere. Here is a simple explanation of what "secure connection" (HTTPS) is - HTTPS and SSL tutorial (video). That should also clarify what different kind of warnings you might see when attempting to connect to a site securely actually mean.
Social networks privacy and security settings
Social networks are extremely popular. Facebook was the first social network to surpass 1 billion of registered accounts. Others are trailing behind but have significant number of monthly active users. This social media comparison infographic gives some insight regarding how the most popular networks are performing. The question is - with such a massive amount of users and resources required to provide the services for those users, how can they be free? The answer:
If you're not paying for the product, you are the product.
Those companies are not offering you free services just out of the goodness of their hearts. They are operating businesses and the user base is the commodity that can be used to make profits. Don't get me wrong, there is nothing "evil" about the fact that a company wants profits. After all, the services you are using cost money and a lot of man-hours, quite possibly with the developers heading home after midnight or QA teams spending weekends testing updated sites.
So those companies would want to know as much as they can about you, to pass the data to advertisers, etc. And this is what you agreed to when signed up. You did read the "Terms of Service", didn't you? :) Well, even if you did, it would not be very easy to understand them, so you might want to check "Terms of Service; Didn't Read", which sums up what those terms actually mean for a lot of companies. You might also find the following articles rather interesting:
- Data collection cheat sheet: how Parler, Twitter, Facebook, MeWe’s data policies compare.
- There’s no escape from Facebook, even if you don’t use it.
- We Checked 250 iPhone Apps - This Is How They’re Tracking You.
So if you are using a social network, you are already sharing your information. You could, however, limit the amount of the information shared. Most companies will give you a way to do that, you just need to check the settings once you've signed up. Below you will find a collection of guides to setting up your privacy options for the most popular networks.