This would require a server side implementation to work well. Unfortunately it looks like Lemmy does not track this.
Summit
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Website: https://summit.idunnololz.com/
Is this a statistic that Lemmy itself tracks? I haven't heard one way or the other, but if it doesn't then I'm not sure how realistic it would be for Summit to implement. It could maybe show you how many times you personally have viewed a post (not sure how valuable that is, though) or how many times a Summit user has viewed a post, but the latter feels like a bit too much data collection for questionable return, imo.
If this is something that Lemmy already tracks, though, then adding an option to view it would be great! More options in general is always my preference, even if I don't necessarily make use of them myself.