No way is this opt-in. The invitation page you display is offered to BT surfers without a by-your-leave or consent of any sort. When they open their browser and try to go to the web page they want, BT intercept their request and give them the Webwise invitation instead. It's called a browser hijack and BT are doing 10,000 of them during this trial - at least, they SAY they are - not a single BT customer has appeared on the BT Beta forums to report receiving this invitation. But of course that may be because they don't want their email address leaked - the BT Beta forums leaked emails all over the internet until last week. BT, the company that wants us to trust them over Webwise, after two covert trials where they misled us and the press in 2006 & 2007, has now shown it is incapable of even running its own customer forums securely. What a shambles. I get my information from www.donottrustwebwise.org rather than from BT. Because I no longer trust BT on either integrity or competence.

so the Opt-In/Opt-Out is bit of a red herring.

Make sure you get a long way downwind "even making that statement" , makes everything mouldier & feistier than I ever thought it would get!

Anyone feeling lucky think this will not stop you earning while paying less for your connection, think again. Any company signing up to BT business packages will lose out in the end as your own websites will become food for competitors, as those visiting on T internet will be shown adverts offering the same, similar so visitors will be enticed away.
Out-out is illegal it has to be opt in but for what it is worth read between the lines. In one place BT say you will not go via Phorm profile yet if you block it your surfing will stop. In another place you are told you will but they will not serve you adverts.

the saying damned if you do and damned if you don’t fits phorm since if you are BT internet customer home or business then you are damned

Even if you Opt-Out by selecting 'No Thanks' your traffic is still sent through the Phorm hardware, so the Opt-In/Opt-Out is bit of a red herring.

i like the way it says "exciting new service"
i suppose 'parasitic' and 'money grabbing' would deter the more intelligent customers(!)

they are sooooo generous in providing this for free. 
i suppose it would also deter customers if they knew bt were making loadsa money out of targetted advertising.

either:
A. they consider their customers to be thick and gullible
B. theyre customers ARE thick and gullible

i hope it fails miserably and bt lose tons of customers. greedy moneygrabbers...