One of most interesting things when blocking third-party content on websites by default, is how web developers handle that. The best example might be captchas.
First, I almost never notice that they're missing. Because they're just embedded without any hint that they exist (e.g. a frame or just „Captcha:“). Second, it's interesting to see what happens when proceeding. Some sites are pretty clear („Captcha hasn't been solved“), some just give you a generic error, some just won't proceed at all.
On the other hand, it's remarkable how many external resources are usually loaded, even though they have no impact on the functionality of the website whatsoever.
I'm using those tools for quite some time now, but I'm still surprised about how much unnecessary stuff is added to websites regularly.
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