Cloud = Vapour
Our Web team use Fontdeck quite a bit for custom fonts, so this is going to hit them hard.
As with the reported shuttering of Adobe's Photo cloud, this does call into question why you would constrain your business to the point of reliance on a cloud based service, which may disappear at any time.
Granted, Fontdeck have tried to do this in the least disruptive way, instead of abruptly disappearing without trace, but if no-one else provides an exact replica of a particular font they currently supply, then designers, developers and clients will all have to start again picking a replacement, which all costs time and money.
So what incentive is there to use a cloud based service, given you could be left in the lurch at any time?