That's like having to get a new driver's license for every state you drive through.
Although the walls that keep users from taking their data wherever they go are starting to erode, how much three recently announced programs will help users move among the networks remains to be seen. Google Inc.'s attempt to break those fortifications was quickly blocked by Facebook.
The two leading online hangouts, News Corp.'s MySpace and Facebook, have promised to release tools in the coming weeks for Web sites to incorporate profile data, friends lists and other social functions. Google followed with its own program for bridging various networks.
MySpace users, for instance, can soon have their biographical information appear on eBay Inc. profiles. A social network focused on skiing will be able to incorporate Facebook photos and friends list rather than build its own.
It's all done through software hooks that let eBay and others grab profile data from MySpace and Facebook. Changes made at MySpace and Facebook are quickly propagated because third-party sites can't store the data and must check back frequently.
The new programs come as users increasingly complain about having to retype basic profile information over and over. By holding onto users' information while letting them bring temporary copies of it elsewhere, Facebook and MySpace can remain at the core of users' social interactions and keep them from leaving.
More important than saving keystrokes, the programs bring along the meaning and connections behind the data, allowing social circles to travel from site to site, much as friends going bar hopping together don't have to start conversations afresh at each pub.
That said, there are no current plans to exchange profile data between MySpace and Facebook. Message postings at one won't show up at the other, and party invites still will have to be copied and pasted to cross services.
Google's new Friend Connect comes close to merging those lives, though. When announced, it was to pool profile data from Facebook, Google Talk, Google's Orkut, LinkedIn, Plaxo and hi5, though not MySpace.
But within days, Facebook began blocking Google, saying it couldn't ensure anyone's privacy if Google were the intermediary.
Such concerns are simply a convenient way to play down underlying desires for control, said Deborah Pierce, who tracks social-networking privacy as executive director of Privacy Activism.
"They get to say, `We're being the good guys on privacy,' but they are still retaining control of your personal data," Pierce said.
Some startups aren't waiting. Minggl and Zude both promise to help users aggregate data from their various networks, including MySpace and Facebook.
There are some legitimate privacy concerns.
"In many models, something becomes public once and it becomes public forever," said Dave Morin, a senior platform manager at Facebook. "We believe in giving users control. If we move too quickly we might not achieve that."