you mean Pocket? I was wondering how well the search there works.
Turns out it is possible to search the pages themselves, but only with paid subscription. In the free version it only searches the titles and urls, like the Bookmarks.
This will probably kill the utm_source as a standard. Companies that want this will blob encode all the fields or rename when generating links and remap back on their reverse proxies.
Looks like Safari in iOS 17, iPadOS 17, and macOS Sonoma will also added tracking removal for copied URLs. According to this article it will only do so in private mode tho. (Why not always?)
Preventing such stripping as a website operator would be trivial. Just sign the combined URL and tracking parameters and refuse to serve the unauthenticated version. This is very well understood technology with a barely novel application.
From what I heard, Facebook already does this, and it was supposedly introduced as a response to a similar anti-tracking measure by Mozilla. Not by signing the URL, but by encrypting everything into an opaque blob.
>?utm_source=pocket_saves
to all saved links.