Favorite obsolete formats.....

Whenever I think of 8 track I remember the rolls of tape used to splice them back together. But it was the first tape format to be in cars and I love driving with music playing.

As far as tin can and string, that may be an upgrade in communication today, since no one under 40 can talk on a phone today but text instead. You know, kinda like the ancients who scrawled messages  on cave walls.. 

Smoke signals have been modified today. No blankets necessary. Just set a city block on fire if you don't like things and don't get your way. Or if you win a league championship you set a building on fire.  You tell the difference between joy and sadness by the size of the smoke. Little means fun. Big means run

+1 @artemus_5

78 rpm.  Much of America's best music can be found in this format.  Not obsolete for me!

R2R, cassette and (FM) radio still very much alive here.

Blankets with fringes and tassels, more info, revealing to the bone.
I used to have also cans with strings to communicate with the neighbour, great times.