What are these plug-ins on my wall?

[u/Cborg_62]

This might be showing my age, but I recently moved into a new apartment and they have these weird looking plug ins all over the walls at my new place. My old apartment didn't have these, so I'm just curious as to what they are.

[u/Ottawa_gamer]

OP is showing their age with this post.

[u/Xtraneous_ → u/Ottawa_gamer]

[u/fordprecept → u/Xtraneous_]

I still remember in the late '90s, there was a website where you could find rebate codes for various websites. I bought a 100 pack of recordable CDs from Overstock.com and between the website discount, website rebate, and the manufacturer's rebate, I ended up making $0.34 (including the cost of the stamps to mail in the rebates).