Jeff's way of getting his C64 online is becoming more and more common. Some use a Raspberry Pi, others use dedicated modems - but all go through the C64's Userport which can communicate over RS-232 serial. Jeff walks through the project on YouTube here, and you can find his code on Github.I connected the Userport to a Raspberry Pi with a artisanal, locally sourced, homemade cable with the UserPort connector on one end, and a usb TTL-RS-232 converter on the other.
At my own office, Slack has become the #1 means of communication second only to voice (and Slack might actually be winning). I seriously think I should invest in a Commodore SX-64 and use it as my dedicated Slack machine, don't you?
UPDATE:
To be clear, the Slack client only works with a Raspberry Pi. In theory one could use it with an existing WiFi Modem but a significant amount of new code would need to be written to support it. One would need to replace the rs232 code with code to talk to the Wifi modem, and one would need to deal with websocket handling and JSON parsing.