Brad Fitzpatrick, the founder of LiveJournal, who recently left Six Apart for Google has published notes on what he's going to be working on moving forward. It is an interesting read entitled Brad's Thoughts on the Social Graph which contains the following excerpts

Currently if you're a new site that needs the social graph (e.g. dopplr.com) to provide one fun & useful feature (e.g. where are your friends traveling and when?), then you face a much bigger problem then just implementing your main feature. You also have to have usernames, passwords (or hopefully you use OpenID instead), a way to invite friends, add/remove friends, and the list goes on. So generally you have to ask for email addresses too, requiring you to send out address verification emails, etc. Then lost username/password emails. etc, etc. If I had to declare the problem statement succinctly, it'd be: People are getting sick of registering and re-declaring their friends on every site., but also: Developing "Social Applications" is too much work.

Facebook's answer seems to be that the world should just all be Facebook apps.
...
Goals:
1. Ultimately make the social graph a community asset, utilizing the data from all the different sites, but not depending on any company or organization as "the" central graph owner. 

1. Establish a non-profit and open source software (with copyrights held by the non-profit) which collects, merges, and redistributes the graphs from all other social network sites into one global aggregated graph. This is then made available to other sites (or users) via both public APIs (for small/casual users) and downloadable data dumps, with an update stream / APIs, to get iterative updates to the graph (for larger users)

...
Non-Goals:

1. The goal is not to replace Facebook. In fact, most people I've talked to love Facebook, just want a bit more of their already-public data to be more easily accessible, and want to mitigate site owners' fears about any single data/platform lock-in. Early talks with Facebook about participating in this project have been incredibly promising. 

It seems to me that Facebook is the new Microsoft in that there are now a significant amount of people who are either upset at the level of "lock-in" they have created or are just plain jealous of their "wealth" who have created dedicated efforts to break their hegemony. It'll be interesting watching this play out.

From my perspective, I'm skeptical of a lot of the talk about social network portability because the conversation rarely seems to be user centric. Usually it's creators of competing services who are angry about "lock-in" because they can't get a new user's contacts from another service and spam them to gain "viral growth" for their service. As for the various claims of social network overload only the power users and geeks who join a new social network service a month (WTF is Dopplr?) have this problem.

A real social network is a community and users don't change communities at the drop of a hat. What I find more interesting is being able to bridge these communities instead of worrying about the 1% of users who hop from community to community like crack addled humming birds skipping from flower to flower.

I'll put it this way, when it comes to email which is more important? The ability to send emails to people regardless of what email service or mail client they use or the ability to import your contact list from one free email service into another when you switch service providers?