The biggest opportunity currently available to publishers is with Facebook. Facebook has something like 24M active profiles, and has only recently opened up to outside developers. This property is still pretty untapped.

While I don't consider these Facebook Apps to be widgets (they are not driven by embeds), it is certainly a form of distribution / syndication that folks should be thinking about taking advantage of.

Some of the numbers coming out of Facebook are astounding. Take for example the music app iLike (this quote is from the iLike blog"

"In our first 20 hours of opening doors we had 50,000 users sign up, and it is only accelerating. (10,000 users joined in the first 12 hrs. 10,000 more users in the next 3 hrs. 30,000 more users in the next 5 hrs!)

We started the system not knowing what to expect, with only 2 servers, but ready with backup. Facebook's rabid userbase chewed up our 2 servers almost instantly. We doubled our capacity to catch up. And then we doubled it again. And again. And again. Oh crap - we ran out of servers! Although iLike.com has a very healthy level of Web traffic, and even though about half of all the servers in our datacenter were sitting unused, idle, as backup capacity, we are now completely maxed out.

We just emailed everybody we know across over a dozen Bay Area startups, corporations, and venture firms in a desperate plea to find spare servers so we can triple our capacity for the continued onslaught. Tomorrow we are picking up over 100 servers from different companies to have them installed just to handle the weekend's traffic. (For those who responded to our late night pleas, thank you!)"

So I'd recommend building for Facebook - if you think you can handle the traffic.

I think a Facebook app that "goes viral" could pose some real technical challenges - i.e., needing dozens of servers right now, but perhaps a more specialized app would be manageable. I've heard some concern about Facebook's control over third party apps, but I haven't reviewed their terms and conditions in detail.

Has anyone seen a widget or similar app in use that would drive traffic back to community? I think to get your members to display it on their social network profile page, for example, it would have to have some kind of cool factor. Show that the person is a "Senior Member"? Number of posts? Titles of last two posts? Something extracted from the user profile on your community site, e.g., on a dog forum, the breed of dog owned? None of this seems highly compelling to me...

This is semi off topic, but as a webmaster/entrepreneur that has always dreamed of having a site/app go truly viral, I've begun to question the "garage shop" web success story. How many one or two man shops could afford to ramp up to support Digg, YouTube, or Facebook levels of traffic? iLike has a datacenter? 10 servers or more? If you are not well capitalized and have a top notch tech staff, you can't deal with the success, and that's about as an ironic statement I can make at this time in the morning.