Silver class on o2 iphone - reward or feint?

I've been sent a text from o2 to say that I've in the new silver level of their priorty club.

Cool.

I admit it - I'm a point collector. I'm nearly in the silver level of my airline club, I'm so very nearly gold at Hilton HHonors ... but what do I have to do to move up a level at o2?

In fact, is there a bronze or blue level in o2's priority club below silver? I've poked around the website and can't see any mention of levels.

Priority Clubs are dangerous things. They play on psychology and for every up there's a down. Frankly, if there's a single level called 'silver' or if every iphone user is slapped into silver (notice how the URL in the text contains iphone) then I'll be pretty annoyed. Why? They're treating me the same as everyone else but trying to dress it up as something I've earned to elevate me above other users.