The blogosphere is ablaze with coverage of Facebook Connect, which the social network is rolling out this week to let its users sign in to other Web sites with their Facebook user name and passwords and share what they're doing with friends.

The move is designed to shear a hole in the typically walled gardens so that users needn't enter their Web identities into site after site. MySpace has a similar offering in the works, called MySpace Data Availability, while Google is working on Google Friend Connect, based on its OpenSocial effort.

Both efforts are based on open standards, while Facebook is using its own proprietary technology, though no one seems to believe this will make a difference where consumers are concerned.

Facebook Connect is also the social site's effort to move past Beacon, that jarring privacy-busting fiasco that let users see what their friends were doing, purchases, entertainment tastes, etc.

Why cross the normally sacrosanct social networking boundaries? The three companies will tell you, with honeyed, philanthropic tones, they want the Web to be more social. Well, sure, but there is also potential for greater advertising opportunities, some folks believe.

Noting that advertisers don't know how to advertise on Facebook, Charlene Li of the Altimeter Group, told The New York Times:

...If you take a group of Facebook friends and put them on a travel site where they are spending more time and generating more ad dollars in a focused area like travel, that is an opportunity ripe for getting revenues back and sharing it.

And now Facebook is taking the lead with Connect, with Discovery Channel, The San Francisco Chronicle, Digg, genealogy network Geni and online video site Hulu joining the effort.

I'm torn by what this means for Google and MySpace. Part of me believes that Facebook rolling out Connect first won't have any bearing on the industry. If these sites are all gunning for partners to open up to then ideally the trinity should grab large slabs of the big social Web advertising pie.

The other part of me thinks Facebook could trounce Google, which beyond big-in-Brazil Orkut has no social network to hang its hat on, and MySpace, whose users aren't considered as Web savvy as Facebook users.

But until we see what kind of bearing Facebook Connect has on Facebook's advertising revenue, we won't know. As IDC noted, only half the people on social networks clicked on an ad, with a paltry 11 percent making a purchase. So, as much as social prospectors love to cry "there's gold in them there networks," no one has found the mother lode.

In the meantime, my guess is MySpace and Google will accelerate their data portability efforts very much the way the three companies all scrambled to announce them back in May. Expect to hear more from both vendors in the next few weeks (or months, eek).

While market share in the long haul may not be an issue with such a big pool of Web site fish to gobble, neither MySpace nor Google want to let Facebook to become the open Web whale. Online, perception is key.