Clicking on a link to a tweet has 1/20 chance of ever actually loading the tweet. All other occurrences are evenly split between loading nothing except the top bar and calling it a day, and throwing an error message. Reloading the directly or using the reload button they provide will usually result in the rate limiting message.
I don’t even bother clicking on twitter links anymore. I just hope it worked for someone else and they paste the contents in the comments.
Pinterest would be up there too. It's useless if you don't have an account on mobile and desktop.
Edit: Just tried it myself, might want to add a -site:pinterest.co.uk as well.
Really says a lot doesn’t it.
Nearly impossible to test properly (or was), breaks the whole html model, results in bugs just like this one.
And yes, rate limits.
Twitter came up with the ui framework "Bootstrap" long ago and it was a game changer for responsive frontend layouts.