This is my replacement for mathb.in, which susam is closing down. There was a problem on his part where people were uploading nonsense.
I want a more minimal service. The idea is very straightforward: encode data in URL parameters (giving a hard limit of something like 1000 characters). Allow people to send these URLs.
This is useful for short messages. For longer messages, you'll either need to have a set of links or use a better tool to communicate math.