T-Mobiles flat-rate data plans, under the moniker of "Web and Walk" have reached 500,000 subscribers (reports Ewan MacLeod of SMSTextNews). At £7.50 per month on top of any regular plan, it's proven good value to many people, but I'm more interested in the problems that MacLeod and other urban dwellers are finding with the speeds achieved. Mobile data is growing, and if the networks are creaking at the moment...