The latest Smoke has a write-up of London's only subaquatic bus route, the 108 (Stratford-North Greenwich-Lewisham), and by my reckoning one of very few that pass the same point 3 times during their run. Anyway, the article briefly mentions the Millennium Busway, built to speed passengers from Charlton station to the Dome. Having no recollection of what this engineering marvel amounts to and finding little online, I decided to take a look while I was in East London yesterday.
The answer: not much. Here it is on a map. Very nearly three quarters of a mile of, well, bus lane, stretching all the way from North Greenwich station to North Greenwich Odeon.
The northern half runs adjacent to one of the Dome's gridlocked access roads and has no stops - the only building it passes is this isolated pub with a terrace of houses behind it.
The southern half runs around the back of Greenwich Millennium Village (where there are two lonely stops), then terminates at a junction with Bugsby's Way (pictured). Buses cross from here into the retail park with that Millennium eco-Sainsbury's. Then it's out onto normal streets.
Under the "Millennium Transit" plans it was intended that buses on the route would be guided electronically, following a buried cable, but the technology was abandoned before public service commenced, partly because of safety concerns. The busway is now used by ordinary buses to get passengers to North Greenwich station slightly quicker, but one day will be part of Greenwich Waterfront Transit, and far in the future that could be converted to trams, finally fulfilling the busway's destiny.