@ Stu Reeves
Ofcom say Phorm should be an explicit opt-in. This means that BT *should* have phorm *off* unless they receive an explicit communication from a customer saying they want Phorm *on*.
Sending an eMail saying we will switch it on unless we hear from you is still an opt-out.
Of course, whether BT will abide by Ofcom's ruling and whether Ofcom has the balls to make Phorm / BT do a real opt-out is another matter.
As to how BT describe Phorm to get customers to opt-in, well, that's another issue relating to Ofcoms testicular dimensions. IMHO they *should* be forced to describe exactly what Phorm will be doing, top of page. We all know, however, that it will be buried in the small print that nobody reads.
What is needed is more publicity so that the general public hear about Phorm and reject it. Its all very well the knowledgeable few rejecting it and pissing off to other ISPs, but as the majority of BT and Virgin broadband users are clueless with regards to technical issues and will swallow BT's "Webwise will protect you" bullshit it is, unfortunately, likely that BT and Phorm will get away with it.
Trouble is the mainstream media, and their readers, are more interested in which celebrity is getting into which other celebrity's knickers than with an issue that could result in all of their web activity being spied upon by a notorious spyware pusher.