The recently launched 7 Billion People is an intriguing application to e-commerce of the real-world psychology behind buying behaviors. As CEO Mark Nagaitis tells us, his new Web analytics system tries to discern in a site's audience different "buying personalities" that marketers can talk with in very different ways.

Most behaviorally savvy marketers know full well that the "single-click theory" of consumer behavior, which hypothesizes that conversions are best attributed to the last click a consumer makes before purchase, is fundamentally flawed. Alan Osetek, Connexion.a's executive vice president, sales & marketing, discusses how marketers can move beyond the single-click model by mapping and measuring what he calls spheres of influence.

Behavioral targeting has widely succeeded in changing the rhetoric and terminology of marketers. Rare indeed is the self-respecting behavioral advertiser who doesn't speak in terms of having a one-to-one dialogue with customers. Yet, as Ryan Okum, president of StreetWise Concepts and Culture, explains, moving beyond the habits of the older impressions-based marketing paradigm requires more than talk. It demands the cultivation of a new skill set.

Until just last week, Rich Frankel was widely known in the behavioral targeting community as Yahoo's leading expert on the technology and senior director of product marketing. Newly appointed as COO of SocialMedia Networks, Frankel is moving his vast experience and knowledge into the social networking space, and so we asked him to reflect on how BT will work in social media applications the company helps developers build and deploy. Joining the discussion is Seth Goldstein, CEO of SocialMedia, who says that social networks are causing a demonstrable shift in online behaviors.

In just a few short years behavioral targeting has moved from a strange novelty (looked at curiously and skeptically by marketers) to an over-used buzz term, looked at all too often naively by marketers as a technological panacea. To make BT truly live up to its potential, however, as Jon Mendez, founder of OttoDigital and blogger at optimizeandprophesize.com explains, marketers need to learn to look at it in another way: less as a technological magic bullet and more in terms of overall strategic optimization.

Not all behavioral targeting needs to sell cars and travel. At the activist and progressive hub Care2.com, causes are the merchandise and call to action has a very specific meaning. The 8-million-member social network for people who want to get involved and make personal changes does lead generation campaigns for 300 nonprofits. With 50 to 75 campaigns running across many different interests, director of nonprofit campaigns, Joe Baker, tells us how Care2 uses BT to match the right people with the right causes.

For larger advertisers, behavioral targeting is no longer a "wish-list" item. It's become an accepted part of the everyday marketing mix, bringing with it new possibilities for extending not only reach but efficiency deep into the long tail of consumers. For smaller advertisers, however, the promises of BT have remained largely theoretical, as Michael Sprouse, CMO of ad network AzoogleAds, explains. Making BT small and advertiser-friendly, he says, will involve breaking the complexity barrier.

Performance ad network AdKnowledge reported recently that in 2007 the number of clicks on its text ads had increased 300%. As president Brett Brewer notes, the company profiles users based on their previous history of interacting with ads, and then distributes that knowledge to publishers for their Web sites as well as their email, search and display channels. Recent acquisitions and partnerships in the social networking space have resulted in a product that applies these targeting methods to the emerging widget marketplace.

In its still-young life, behavioral targeting has already taken the notion of one-to-one advertising from visionary theory to everyday practice. While BT has put customized advertising to consumers on the agenda, its next big challenge, according to Robert Tas, CEO of Active Athlete, will be to bring a one-to-one approach to brands by offering true customization of behavioral segmentation within verticals.

You can't get much closer to the full depth and breadth of users' behavior than tracking their clickstream and activity from the time they get online. This is what ISP-level behavioral tracking can offer service providers as a way to monetize their otherwise "dumb pipe" and to ad networks as another way to target campaigns more accurately. After years of watching the approach succeed in Asian and European markets, U.S. service providers are only beginning to consider implementing it here. Front Porch, works extensively in Asia and helps monetize the largest free ISP in Europe, FreeHotspot.com. Derek Maxson, Front Porch's …