I've come across lots of interesting redefinitions of bi and definition pairs of bi and pan before. However - and I can't give you the link as it's one of the million web pages I've read this weekend - this weekend I came across a genius new one. I paraphrase mildly as I read it a short while ago...
Bi is if you have sexual relationships with any gender, pan is if they are romantic relationship
Wow. How brilliantly creative is that? There are these two words, right, and we know that 'bi' is the untrendy one that means you're not in with the cool crowd, but they seem to mean the same damn thing... it must be possible to come up with some kind of definition that splits them apart!
These kind of "bi is not the same" definitions always seem to involve pan being somehow morally superior. I think that might be the tell that gives away an attempt to make yourself more acceptable, the sad old theme of putting another group or identity down in order to raise yourself up in the social rankings.