I've encountered several sites that broken with blocked third-party cookies. Most of the website for one local bank around here and a payment form for a local

I've encountered several sites that broken with blocked third-party cookies. Most of the website for one local bank around here and a payment form for a local puppet theater are the ones that come to mind offhand. Typically, it'll be small sites that are outsourcing part of their site to a third party but don't want to open a separate tab for that which will be affected by this, obviously. If you only browse major sites doing everything in-house you're not going to run into problems.