Those claims have on occasion been driven by commercial opportunism (nothing like good news to pump up a flaccid share price or buff a stodgy corporate profile), incomprehension or indifference on the part of the mass media and the tendency of 'citizen journalists' to drink the digital koolade. The reality is - and will remain - that although broadband (however defined) can be delivered via the conventional electricity grid, such delivery is fraught with difficulty and is not commercially competitive once steps are taken to deal with radio interference and other problems. (I've noted that is also possible to deliver the net via carrier pigeon or bongo drum ... both mechanisms are technically feasible but, how very strange, have not supplanted wireless, fibre or conventional copper.)
I can thus empathise with the following response to reports that a 'smart meter' trial in Liverpool (UK) will lead to householders enjoying broadband over the grid -
Will this minion of the undead ever get a stake in its heart. Please ... silver bullets, garlic, wooden stakes, holy water something! anything!!!Small scale Australian trials, under the auspices of ACMA, of BPL have gone nowhere - typically distinguished by deliriously upbeat media releases (and equally uncritical reporting) followed by an embarrassing silence as implementation does not eventuate. Across the world BPL solution vendors have packed their kit and slunk away; urban and rural showpiece projects have fizzled (eg here).
BPL continues to be "the technology of the future ... and always will be" - bright forecasts, dim reality.