Some hints of what's ahead emerged this week at Facebook's F8 event in San Francisco, where I stocked up on T-shirts, nachos, and "Rock Band" tips. It was like summer camp, except the cool kids were developers rather than athletes, and the camp happened to be worth billions of dollars.

One of the highlights from F8 was getting more information on Facebook Connect, which will debut in the coming months. Here's a rough idea of how it will work for Citysearch, one of the program's launch partners:

1. Someone visits a restaurant listing Citysearch. She's not currently a registered user.

2. She wants to contribute restaurant reviews but doesn't want to register for Citysearch. Fortunately, Citysearch lets her log in with her Facebook information.

3. By logging in that way, she now has a number of features open to her on Citysearch, such as seeing which of her Facebook friends reviewed that restaurant, and the ability to share her ratings on Facebook.

Citysearch can expect a number of benefits from such an implementation of Facebook Connect:

1. More visitors should participate since there's no longer the registration barrier, at least for the visitors with Facebook accounts.

2. Those visitors logged in through Connect will probably spend more time on Citysearch than they would have otherwise.

3. Connect-registered visitors will wind up sharing some of their Citysearch activities back on Facebook, exposing Citysearch to a broader audience, with potential to build traffic and brand awareness.

As more people spend more time on Citysearch, pageviews will increase. Citysearch can then push its local and national advertisers to increase their ad spending, especially for businesses targeting the 18-35 demographic that should disproportionately take advantage of Connect-enabled sites.

Facebook Connect is just one example of how the registration model is changing. Google has the similarly named Friend Connect, MySpace launched its Data Availability Project, and then there's the OpenID platform. All empower publishers to let consumers log in to their sites with an existing third-party account.

It's still too early to tell exactly how all of these authentication options will affect the relationships publishers have with their audiences. Think of how site registration works currently: publishers can request as much user information as they want and then choose how to communicate with those users, whether through enhanced ad targeting, email newsletters, personalized site functionality, or other options. What happens when publishers give up that control?

This will all present three overarching challenges for publishers:

1. It's unclear how publishers will be able to communicate with users who register through third parties. 2. The third party has the right to change the rules along the way. What may be acceptable when a program launches may not be down the road. All of the third parties will be able to set different rules.

3. The changes won't happen overnight; there are many limiting factors. Some publishers will choose not to participate. Others won't have much of a reason for users to register and thus won't be affected. With Facebook Connect, any consumer who's not on Facebook will have to decide whether to register the old-fashioned way.

As much as publishers will benefit from third-party registration, the biggest beneficiary is going to be the third party. It's the third party that will set the rules and control the nature of the relationship between the publisher and consumer. That gives these third parties infinitely more power than they've had previously -- when they were publishers, just like everybody else.