> On a different note, I sometimes use Instagram and recently I have seen a ton of ads for a local tech event... but the event already passed a good while ago, so every time I see the ad it's completely pointless.

I get a lot of these for elections which already took place... in places I don't even live. It seems like these are mistakes on the part of the people placing the ads, it's hard to imagine they're seeing the view metrics from after the event and deciding to keep spending.