Telemetry

If you're unfamiliar with telemetry, it's an automated process of sending data from your computer/apps to one or multiple destinations. This is something which used to be useful years back at figuring out how to fix crashes, but it's now turned into yet another data privacy issue. Almost every app you install these days expects to have internet access and unless you run a firewall with a block by default setting, these apps will be phoning home every time you launch an app and while the app is being used. In the case of an OS like Windows, this happens every minute the OS has an internet connection. This process is now used to collect irrelevant data for the sake of data collection. It's a problem even with many games, even single player, which will try to connect as soon as they are launched. This section will be focused on the generalities of telemetry. If you want to block this from Windows, refer to the Windows telemetry section.

Here's a sample of things that get collected in this process - location data, network data, user behavior (which specific buttons are clicked, changing settings, opening certain menus), error tracking, device info (OS version, computer specs), and overall usage (when you launch the app, how long you're using it). Generally, software from large companies is going to be a bigger problem with this than an open source app. While I see some open source apps try to connect to the internet on every launch (even if it's not needed for the app to run), it's not nearly as much of an issue as something like Adobe, which will run software legitimacy checks whenever it's in use. You'll see telemetry in browsers, games, operating systems, office suites, etc. This might sound like a huge issue, which it is from a privacy perspective, but once you learn how to control it, it becomes a minor issue compared to most other problems I cover on this site.

To give you a clearer picture of why this is something to care about and keep control of; it’s a security and privacy risk, as well as more info that gets vacuumed up for data breaches, it can be abused later on (maybe the data collected is to help improve the app but then gets used to market to you), and it's an overall waste of your resources. Even though it's a small amount, it's still a waste of processing power and bandwidth. There's no need to worry about developers needing the data either - they'll be collecting it from all the others who don't know or care enough to block it. Since you're reading this site, you're here to fix this problem.

Here's some steps you can take to control the problem:

Operating Systems: On Windows, you can start with the "Privacy & Security" section in settings and toggle off anything that's a privacy problem. Beyond that, it's important to be comfortable with navigating and using Group Policy. This is only an option with Windows Pro and up. Home users can still use other methods to block telemetry, but they'll have less control from OS settings, which makes the firewall more important. For detailed info about this, refer to the Windows section, where I cover telemetry in-depth.

If you're on Apple, you can make the most important changes from the settings app. It'll take opening multiple menus to catch all the privacy settings. A firewall for Mac is worth it and I recommend it as much as I do for Windows PCs.

For Linux, I recommend not using a distro that wants to collect telemetry, even with the user having the option to out-out. This is going to be controversial for some - Linux isn't something that should have telemetry enabled by default. Fedora made it an option to opt-in a while ago and a lot of people got upset about it and understandably so. For now, it's not forced on the user and it has to be manually enabled to start collecting data. Because there's a ton of distros, you'll have plenty of choices to choose a flavor that suits you the most. I would recommend doing some research on them ahead of time to make sure the privacy good for you, since not all distros are created equally. Similar to above, I recommend the use of a firewall on Linux as well, so you can fine tune what apps can call home.

Browsers: The browsers commonly viewed as being somewhat private, Brave and Firefox, do have some data collection in them by default. It'll take a few minutes of clicking through all the settings to fix this, but once it's done, they're great browsers (just be sure to add uBlock Origin to FF). If you want excellent privacy settings by default, Librewolf, Mullvad Browser, and Tor are great options. The Big Tech browsers like Chrome are terrible from a privacy perspective, even with the settings being tweaked, though that doesn't mean you can't or shouldn't use them - you'll have to make the call if it's something that makes sense for you to do.

Other Apps: Games and office suites are other apps that commonly collect data. Open source options are better suited from a privacy perspective than Big Tech apps (e.g. GIMP rather than Photoshop), though you'll sometimes lose nice to have features from more well known apps. Sometimes it can make sense for an app to request internet access from your firewall, even if it doesn't seem like it at first glance. For example, in Skyrim and Fallout 4, a player can download mods from in-game, so the internet connection makes sense. In some cases, the data collected isn't anything that would benefit you (e.g. Paradox uses telemetry to determine the most popular nations in HoI4, focus tree selection, etc).

Other than changing settings, you can block some of this through network security settings, depending on the telemetry collector. For example, Windows is a well known privacy problem, so some devs have made firewalls (Simplewall, Portmaster) which can block connections from the app that MS uses to collect data. This can be done with IP blocklists, domain blocks, and app filtering.

Another way to do this would be through the use of encrypted DNS (with built in filtering) and good router firmware (e.g. OPNsense) with proper configuration. I'll stress again, this isn't a catch all. It depends on the data being collected and how the security settings have been configured. I've never seen DNS filtering block something such as an internet connection to a single player game, but maybe you would want those connections blocked, so you'll still need to use a firewall.