Proposed feature for Safari: Markup.

Highlights and notes, with Pencil support, as an overlay atop the original page. Personal, not public, but synced via iCloud. I’d use this every day.

@gruber would it save your annotations to the safari page and you’d have to like keep the tabs open? (Don’t make us have as many tabs open as you do😂) or have it like save to files?
@tday891 No of course it shouldn’t require you to keep the tab open. It’d be saved (and synced) like bookmarks.
@gruber @tday891 It'd need to save the page contents as well since those could change at anytime. (Even if the page content is generally stable, any dynamic elements like comments, iframes or ads are bound to change.)