I thought Sony was past breaking the PS3 with firmware updates, but apparently not. Thanks to Firmware 2.70, many PlayStation 3 owners are finding themselves no longer able to stream media from NAS devices.
The problem seems pretty widespread but a bit of probing suggests that the reason behind the issues is Sony making the PlayStation 3 stricter in its dealings with DLNA servers. The annoying upshot being that - arguably - the issue isn't Sony's but rather a laxness in the way some media servers handle the files they're streaming.
Luckily updating my ReadyNAS NV to a newer, beta, firmware, fixed the issue but having to do so was a pain in the proverbial. Alas for some of you there is no such respite.
Sony is supposedly working on a hotfix post-haste; in the mean time get exercising that patience.
Thanks to everyone who called Sony out on this one - there's more of us suffering that I would have thought.