Gamasutra - What Is A Step Too Far? On Ubisoft's DRM Policies.
It's important to understand that this isn't the developers' fault. This is purely Ubisoft as publishers placing this down. We're not seeing this purely coming out of one of their studios; it's a universal thing, placed on every single one of their PC games. It's all about the publisher's bottom-line, and completely not about what it thinks of the PC gaming audience. It thinks piracy is hurting it, and this is its move to counter that.

And it might work. Part of the DRM is that the online connection is required because the publisher isn't shipping the entire game with the disc; part of the code is supplied by its servers, which is the reason for the constant online connection. The game disconnects when you do because it simply can't run without being online. It's not like it makes everything all right, but at least there's a reason for it.