The Compulink Information eXchange called itself a "computer conferencing" system. For a one-time registration fee of just £25, plus £45 for the off-line reader, plus 6p a minute standard rate or 4p a minute cheap rate (minimum monthly payment £6.25), you could have access to their Free Internet Mail service. Usenet, ftp, bulletin boards ("conferences") and files to download were also available.
I never joined on account of how I had a free CompuServe account, but there are a couple of membership forms in that plastic envelope if anyone wants to give it a go.