Let's ask Twitterfall, shall we?
tbush: Bugger! Frantically trying to get Michael Jackson tickets via the O2 customer site and the site is down. Not cool!
tkei: Wife is trying to buy tickets to see Michael Jackson in concert and the servers have crashed. No surprises there really.
Boborato: Here we go once again for Michael Jackson's tickets... stucked on "Your wait time is approximately 15 minutes or more"...
patrick: Wow after 30 minutes in line for Michael Jackson, the website updated.... now approx 14 minutes wait time :)
monodot: Dumped out of the queue for Michael Jackson tickets after half an hour with a "could not complete your request" msg. Try again....
Of course, it's not all doom and gloom:
DanAYC: has bagged 4 tickets for Michael Jackson at the o2 arena, cant get back to sleep! WWWWWWWWWWWWWWWWHHHHHHHHHHHHHHOOOOOOOO HHHHHHHHOOOOOOOOOOO
Well, if you can count 'getting tickets to see a shambling legend effectively reduced to busking' as some sort of win.
Of course, Twitter is a self-selecting sample, but it seems for every happy customer, there's eight or nine people suffering from Ticketmaster's inability to manage, seemingly, any large scale demand for tickets. Which you might have thought would be their key business.