UPDATE: This had been resolved, but new problems have begun on 2/11.
Ubisoft has confirmed that Uplay, their PC client (UPDATE: Ubisoft has clarified that the Uplay client on all platforms is impacted) that acts as a hub for all things involving their games, is down for many around the world. The initial reports stated that the problems were caused by out of date Uplay clients, with support pointing people to the official website to update. However, many said that the client offered on the site was itself out of date, and that the issues persisted even after updating.
At this point Ubisoft support is simply telling players that there are issues, that they are aware and working on them, and to “bear with us while we investigate”. This issue has been going on for less than an hour so far at noon Eastern Time, so there is the possibility that it is small in nature, and easy to fix. With Ubisoft working on it already we’ll just have to wait and see how it turns out.
Uplay has been a contentious piece of software ever since it was released by Ubisoft. The Steam competitor had some issues, many of which have since been worked out, but a lot of players simply feel that it is an unnecessary bit of complication added on top of their games. Ubisoft has pulled back somewhat on their adherence to Uplay, so perhaps fan reception will improve soon.