When you share a youtube link you may notice an ?si=(random gibberish) at the end. You may notice the same with Instagram, except here it's ?igshid. On Twitter, it's ?t. On TikTok and Reddit you have urls that end in gibberish like vm.tiktok․com/blahblah or reddit․com/r/blahblah/s/blahblah.

These URLs are artisanal. They are made only for you.

Other site's URLs can also be called "high entropy" URLs, for example, they may contain the time down to the millisecond, in one case.

When you share these URLs to the world wide web, you broadcast to this service (to YouTube, to Google, to TikTok, to Reddit etc.) that "Hey! This previously-anonymous account is actually me!". When you share this link to your friend halfway across the world who only talks to you on Discord, and they click it, you broadcast to this service that actually you two are buddies. Same here on Hexbear. This sharing helps these sites build a social graph on us.

The threat is two-fold. Google has a powerful search crawler, and also runs a massive ad network. They could sift through the pages they indexed on Hexbear and link the exact Hexbear account to your real name. People who have clicked on your shared link will also be exposed as having been on that exact page to which you shared the link. This kind of metadata leak can be dangerous, as law enforcement has previously asked Google to reveal people who watched so-and-so YouTube video at so-and-so time.

This bot also handles TikTok, Yandex, Snapchat, Meta/Facebook trackers that all have this same ad-related threat.

If you're a mod and you think this is important, you can @ mention this bot on a community you moderate. The bot should reply to you with some cringe, and then you can appoint it as a mod. When given mod powers, it will remove any comment/post that contains tracking links if the user has not fixed it after a day.

I will probably add functionality to sift through old comments that have dangerous trackers (like TikTok, which exposes your name and picture to anyone who clicks it) and remove/report them soon.

Install the ClearUrls extension on desktop (if you're on Chrome... please switch, that is another privacy issue entirely). ClearUrls will cut down on most of your worries.

Be on the lookout for the high-entropy parameters when you share things on your phone as well. Parameters in the url that look like ?si=blahblah, ?igshid, which look like they'd stand for "share ID" or "Instagram share ID", as well as obfuscated TikTok links like vm.tiktok․com/blahblah will all track you and your social circle.

If you're browsing a sensitive website, like Hexbear, and you happen to click a tracking URL that goes to YouTube, Google/YouTube can correlate your click with the appearance of this URL on Hexbear, associating your identity with this site.

To avoid this, you may use Firefox Multi-Account Containers, and make Hexbear use its own container that you keep separate from everything else. Although this solution is not perfect, it will prevent one facet of your identity leaking and make it harder for other sites to correlate your digital footprint.

The biggest threat is TikTok, which basically doxxes you when you share a link with someone.

When someone clicks your TikTok link, a big banner on top of their screen shows your profile picture and your name. If you used your real name and picture... well. Uh-oh.

Other "light doxxing hazards" exist on other sites. After looking through Hexbear comments using the search function, you can find comments that link to *****, comments that link to ****, etc. that may include the user's general location down to the city, their preferred language, their screen width and height (in the URL!!! for some reason???), and some very high-entropy parameters that look like a long string of gibberish.

If I sat down today and looking to dox someone by looking at their profile and they shared links willy-nilly, I'd have some pretty good leads.

HexReplyBot does not handle YouTube tracking parameters properly. The maintainer can check this RegExr post I made with the modified regex. I bodged it real quick, but it should remove the ?si at least. It will still keep the ?pp parameter, but I got lazy and it's not as common. Please consider changing the regex out, thank you.

https://archive.ph/8c80m - law enforcement using metadata provided by YouTube to find the real name of a suspect
https://hexbear.net/comment/4439859 - someone mentioning that they keep getting a Hexbear user recommended to them on TikTok because they clicked that user's TikTok link months ago
https://archive.is/WD7ke - "We kill people based on metadata" Can't be bothered to find it but ross ulbricht got busted on some metadata links between his email and stackoverflow. Now imagine if they had tracking links back then to triangulate his stackoverflow identity (which now has tracking links) with some other offsite identity.