They are "Planet On Line". They're the company that provide Freeserve with its ISP type stuff.
Freeserve is/was launched by Energis - network, telephoney, backbone, Dixons group doing marketing, and handing out CDs and Planet OnLine - who were a medium sized ISP back in the early days.
[contradicts Diddlydaz -- does Freeserve resolve to its own domain now? used to be the case that it all showed as pol.]