Sony Ericsson is making an attempt at making their phones, the best option in terms of Social Network integration. For starters Facebook will come pre-installed. Considering that almost every customer would be downloading the app anyway, this is a good idea and allows them to integrate Facebook into the core software.
Facebook has been doing everything it can to become a necessary service. They have gotten their Share and Like buttons spread across the web in a massive way. This goes along with their single sign-on service that allows you to simply connect your Facebook account to an app as your login information with a single click. In mobile space this feature is actually really convenient, and takes away the hassle of inputting all your information for each and every service or app.
While this may give Sony Ericsson a small edge in marketing its new devices as being great social networking devices, they are going to need to show that they can be dedicated to devices in terms of software upgrades.