The underlying problem here is workflow.
People are leaving tabs open as a reminder of things to which they intend to return. (Regardless of whether they will or not; that's another discussion.) And they're not bookmarking, because bookmarking begs organizational overhead, which leads to its own mess. (neither tags nor folders are great or sufficient)
And who knows if a bookmark will still point to the content you intended, when you finally get back to it?
So the problem is ultimately that bookmarking is broken, both for quick reference and longer-term storage. So why not fix that?
Why not a system where bookmarking a site saves a copy to a (cloud-stored) cache. [1] And then searches can be done on the content in that cache. And hits can be served both from the cache, and a simultaneously downloaded 'live' result, available with a toggle. [2]
So that one can bookmark a brag-post about a neat jquery-enabled dropdown list and not have to worry about categorizing it, nor whether or not it will be there in a year, and be confident that they can refer to it again with a simple search of any of the key words that occur to them. [3]
[1] Because one can never know what will happen to content online (changes, broken links, takedowns, etc) and doing a federated search across thousands of bookmarked sites looking for 'jquery dropdown' is going to be a nightmare.
[2] Room here for a great feature of non-trivial difficulty: change-detection and display of diffs (if any) rendered in-line.
[3] Or even searching by meta-data such as date-of-bookmark, location or source-device. "That thing I was reading on my phone last spring, when I was stuck in Chicago on business..." can be surprisingly useful when searching.