It would be more effective to ask the authors of the existing plugins (no one of them is made by me) to add this feature.
..and it makes them invisible in Firefox. You are right.
Fixed by recoding archived webp images to png.
I would really appreciate if you suggest a better translation! Please, send an email to webmaster@archive.today
Fixed, http://archive.is/fACRv
It is made by Tumblr, not by me.
You can always use email to ask questions.
There is no explicit per-user limit.
There are some performance limits derived from the limits of the hardware: for example, the number of running browsers is limited and the queue size is limited.
They are very rarely hit, but the user willing to submit tons of urls has good chance to hit them.
1. same pages like in your example are very rare. ads or block of recomedations or feed of tweets differ.
2. it might take considerable time to make a hidden snapshot to compare the previous snapshot with; also this operation may fail due to network conditions or server error.
3. for some usercases it has sense to same exact the same page twice, to proof that it has not changed.
Images are deduplicated, htmls are not. There are too many images which are the same across thousands of snapshots; for example, the icons of the social networks
Could you help the free project and improve the translation?
Alternatively, you can change the language: http://www.w3.org/International/questions/qa-lang-priorities.en.php#changing