From a variety of websites including (all text below from) London Reconnections:

TfL appear to have begun public testing of the new online service for tracking buses via Countdown. The full list of Countdown locations was recently made available on the TfL website recently, giving an overview of where this is likely to prove a useful service.

The service allows users to specify a street or postcode (as with the Journey Planner) and then select bus stops via a map. The live bus departure times (or rather those trackable via Countdown) are then then shown. It's an interesting service and one which will likely prove popular.

The BBC also have an article up about the service (complete with guest quote from Diamond Geezer) and include the following comment from TfL:

A TfL spokesman said: "TfL has commenced user testing of the new 'countdown' system which will provide real bus arrival information for all 19,000 bus stops across London via the web and SMS.

"The existing roadside sign service is currently limited to 2,000 bus stops and this new service covering all buses and all stops will launch fully in the autumn of this year."

It seems likely that an official launch of the service will follow after this initial trial is complete. In the meantime, readers wishing to use it themselves can find it at http://countdown.tfl.gov.uk.

I remember being told this was on the cards and was just thinking this morning that there had been no news for a while.

It looks genuinely useful - you can save your favourite stops and filter out routes that you don't use. It's going to make those decisions about which route to take so much easier when the 'slow' option arrives first!

You can also look for a bus stop using a route that serves it if you don't know the postcode etc.

And while I'm looking forward to it being incorporated into my favourite 'Journey Planner' app, there is a mobile version of it here.

It's really good, but I still want to see Countdown boards on London Road.

Doesn't work for the 356 bus. But others seem okay although I haven't tested much.

It can sometimes be difficult to work out which bus stop is which on the mobile version. It also includes some bus stops that no longer exist (London Road opposite Taymount Rise). However, on routes that are supported it is very useful information, even if you have to guess which stop you are at.

I've managed to get 356 data on my phone using the London Road/Forest Hill Station stop towards Upper Sydenham and the Savacentre stop in Lower Sydenham.

However as it's a low frequency route, it may be down to the fact there's no bus within the local area for it to pick up GPS data.

I think they've scaled back the data they're providing on the service from 30 mins ahead to 15 mins ahead. Possibly as a result of the URL of the beta service leaking to far more "test" users than they were ready for, and getting too much traffic.

With the 356 being a once-every 20 minute bus during the day, and once-every 30 minutes at night, this means that at times there appear to be no 356's due at any given bus stop. The 356 appears to be working more-or-less as well as any other route on the site to me.

Applespider - big thanks for putting that link up!

I've often been frustrated waiting at bus stops without a tracker installed and have already used this 3 times in 3 nights so it's been a massive help already.

(doh - and thanks to Michael for initiating the thread with his tfl web link! )

Both mobile and web versions are excellent with a fairly high level of accuracy over 7 or 8 routes used by us locally.

Use for the last three weeks on these local routes has shown about 95-97% accuracy with only one route in exception - the old and trusty 356.

Omissions are the most significant issue on the 356 route - you may see a 356 at say 19 minutes away, for the 356 then to drop off the display when you refresh and to then to stay invisible until the last few minutes (typically 3-5 minutes) before arrival - or indeed not at all; on other occasions you may be shown a 356 at say 25 minutes distance then to see a bus arrive a few minutes later completely unannounced, ie a correctly timetabled bus that has not been picked up by the countdown system.

However the system is a real game changer and on a wet or windy morning makes a huge difference to the times spent waiting at the bus stop itself - and as we are reminded, the system is only in the test phase.

Commendable work by TfL.

I've experienced similar issues with the 363 bus. Check the site and it'll say 15/20 mins then 5 mins later it magically pops up with 4 mins to go.

I have a feeling they have some GPS issues in the Sydenham Hill area which may also affect the 356.