Canonical link for sorting topics pages

Question

Should I add the link rel="canonical" tag to sorting topics pages?

Stack Exchange would be a good example for my question:

https://webmasters.stackexchange.com/questions?page=4&sort=newest
https://webmasters.stackexchange.com/questions?sort=votes

Why is there no canonical link pointing to https://webmasters.stackexchange.com/questions? As far as I know, crawlers would still crawl these pages (to follow the links and index the topics).

If the answer is that the query string (e.g. ?sort=votes) makes the canonical link directive useless and every page is treated (page rank, they're not indexed, etc.) as https://webmasters.stackexchange.com/questions anyway (would the canonical link change anything?), I have another question.

Let's say you use a custom parameters for sorting (so there's no query string):

https://webmasters.stackexchange.com/questions&page=4&sort=newest

In this case, should link rel="canonical" be added? Or should I let search engines to index every single "questions" page? Would there be any drawbacks of such solution (no query string + canonical)?

Answer 1

With the two examples posted as there are many paginated pages and you are sorting by variables which change the content in large sections across many pages, so you wouldn't add a canonical tag to the main page, as the sort pages do not contain the same content.

Is it okay if the canonical is not an exact duplicate of the content? We allow slight differences, e.g., in the sort order of a table of products.

Taken from Specify your canonical

If the sort pages were on a single page then you could use the canonical tag, as that same content only appears on a single page, but not in this case.