But when asked how many of those viewers had actually loaded the widget onto their page, the numbers dropped to about 15-20 million for RockYou, and 30 million for Slide--roughly one out of five for both companies. This distinction between page views and actual user engagement with widgets (and ultimately, the brands associated with them) was a focal point of the panel's discussion.

According to panel moderator Seth Goldstein, CEO of the Facebook ad network SocialMedia, the widget "users-to-viewers" ratio was an important takeaway for all marketers in attendance. "The big numbers you hear are people that are passively encountering the widget," said Goldstein. "And any time a company can throw out [stats] in the millions and billions, that's a sign of where dollars are going to go. But it's the level of engagement for marketers that's the question mark."

Goldstein also tasked the panelists with spelling out the difference between portable applications and widgets, as the terms are often used simultaneously--adding "confusion to the hype" surrounding a medium with clear, but slightly misunderstood, potential.

According to Sonya Chawla, senior director of ad sales at Slide.com, "We're open to every platform. Some people call them widgets, Google calls them Gadgets--but we call them TV boxes internally because it's like letting users take a little TV and put it on their own profile pages."

"A widget is a simplified app," said Maurice Boissiere, vice president of client services of the widget development and management firm, Clearspring Technologies. "They can have dynamic functionality, like the ability to make content fresh and relevant, but not the two-way communication of a deep application that's fully integrated into a social graph like Facebook. But I think both terms will stay around."

The panelists agreed that publishers or advertisers planning to use widgets need to make sure they have enough quality content to feed them with and an actual strategy for promoting them--because widgets don't just go viral by chance. "Viral growth is engineered," said Goldstein.

"You can't just build a widget, put it somewhere and they come," said Boissiere. "The initial burst comes from seeding a widget inline with content. Users are going to NBC.com for content around 'The Office'--they're not going to go to Facebook first to get that content."

According to the panelists, the recent wave of publisher and advertiser interest in widgets was arguably tied to Facebook's decision to open its platform to developers. "With an app on Facebook, you as an advertiser can build a multipage experience that goes beyond just a widget," said Ro Choy, head of business development, RockYou. "You can create a microsite in a user profile."

Choy added that the widget's success also depends on building real functionality into the application. "You have to create an experience--a reason for users to invite their friends to that application," said Choy. "The engagement of the social network user is tied to the platform, so if it sits directly on the page, it's easier for a user to invite their friends and engage with it."

Chawla added that applications and widgets are the way to go for advertisers targeting social networkers, as brands like Cover Girl and content partners like MGA Entertainment and CNN have already run successful widget campaigns. "People are so engaged in the social network, if you require them to leave to monetize them, you'll never win," said Goldstein. "It's selling against what they want to do. You build an app where they stay, and you use it for branding, direct response or to get some data."

This news story is important. I recommend that everyone read it.