I used packet radio around 1997 before we had an internet connection at home. It was fun to discover and hop from node to node while listening to the data being transmitted through cb radio. It was really slow, but it could handle some small file transfers. Text communication worked best and it was even possible to encrypt the messages. I think the software I used was called graphic packet. Good times.

Edit: Found a screenshot online. This is how graphic packet looked

I've been curious about the same thing. I have an RTLSDR usb that I used to have connected to a huge antenna, mainly to listen in on GMDSS DSC transmissions on the 8MHz band, so I could use that to plot ships around the world.

I've since moved, so I no longer have a dipole in my yard, but I need an excuse to build one.

Not quite packet radio, but there’s a huge community for FT8 (very very limited communications bandwidth), there’s also JS8Call, but it’s sort of slow right now (on 20m at least). You might be interested in SSTV; there are various bands of activity, some on 20m (14.230Mhz and 14.233Mhz) and certainly other bands as well. The advantage of SSTV is that the more popular platforms (MMSSTV, BlackCat SSTV, and fldigi) can take audio input from your sound card and convert it to the SSTV broadcast.

Pair that up with any WebSDR and you can get nearly any broadcast within reach of your browser and the WebSDR in question.