[Disclosure/reminder: I head up marketing for Plaxo.]

In a piece not-so-flattering to Plaxo over at TechCrunch (it’s okay, I’ve developed a thick skin), Erick Schonfeld shined a spotlight on the invite-only beta launch of a new “address book sync” startup from the Netherlands, Soocial. According to the post and the company’s website, they’ve developed a multi-way, automated sync solution for address books, very much like a piece of functionality which is a core part of the Plaxo solution.

This blog, dedicated to the emergence of the open Social Web, with users owning their data and having the freedom to take it with them between all tools and services, applauds the arrival of Soocial. And, as someone who has worked at Plaxo for just over two years, I also welcome them to what I call the “deep end of the data portability pool.”

What do I mean by that? Automated, multi-way addess book sync is the Holy Grail of data portability. When it works flawlessly, it is damn-near magic. Make a change in any one tool, and it automatically shows up in all the others. Your hard drive crashes? Not a problem; there’s a copy in the cloud.

But behind this “magic” is some of the hardest work in the software business. Why? Rock solid APIs are few and far between for the various tools, and in the absence of such APIs, any company that wants to do sync has to jump through a bunch of technical hoops to make sync work at all. Oh, and if in jumping through such hoops, something goes a little bit wrong? There is Hell to pay. Sync is an unforgiving master. Mess up a person’s address book (in all the tools they use), and you may lose that customer forever.

Soocial claims to sync with just about everything out there, from mobile phones, to the Mac, to GMail, but there’s a gaping hole in their coverage for launch: Microsoft Outlook. Oh, the tales that could be told about the fine art of syncing flawlessly with this ubiquitous tool! Colleagues at Soocial, we know the pain. (Vocabulary word: “thunking.”)

But, no matter, this is great news all around. More choices in the market is always good. Users love it, and vendors are forced to make their offerings better, and to double-down on differentiation. It will be interesting to see if Soocial can overcome some their current scalability issues and round out the offering with a high-quality Outlook sync (and unveil a business model; current offering is free).

Data portability remains really hard work; let’s hope that the industry’s collective efforts make all this simple, easy, and universal!