The object is to post something that was once common, but has gone out of favor, use, fashion, or whatever. When someone reads it the ideal reaction shoud be, "Yeah - I remember that! Haven"t even thought about it for years."
Don't make it obvious, like "Penny candy for a Penny". If you don't know what someone else posted, feel free to ask. I'm sure some of these things will be unknown to the younger folk. Things like:
Dimmer switch on the floor/firewall of a car.
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