Another outlet for web widgets that is often overlooked are personalized homepages. Microsoft's Live.com, Netvibes and Google are just a few of the sites that offer anyone the opportunity to deploy a widget that appears to users as a personalized web portal. To many users, this page is what they consider "the beginning of the web." At the very least, every new browser window opens with your brand holding a piece of that screen real estate.
Aside from the obvious benefits of making a brand accessible through internet start pages in terms of reach and frequency, there is a tremendous PR upside. Web widgets like these tell a story of brand innovation and accessibility that practically writes itself -- for both the brand that develops the widget and the web platform.
Let's take a look at Slide.com as a way to understand the underpinnings of a well-done web widget:

The most popular widget out there according to comScore's April widget ranking, and Brittany Lawson's recent iMedia article, has, like most popular widgets, a very basic and singular idea at its core: an easy way to make a web-based slideshow out of your pictures.
Most people can't make their own Flash picture slideshows, but Slide.com solves a basic problem. They provide the functionality (an easy way to make slideshows on a website), and you provide the content (your pictures) and the promotion (sending people to view pictures on your site). They also do the coding legwork for you depending on the social network you need to put the movie into. And since Flash can handle video and audio, Slide has created ways to connect brands and users together through its own platform.
The easiest way to understand how Slide works is to think of it as a site that makes very small Flash websites. A user goes to the site, creates their Flash movie via the interface and saves it.
This is the key: they have to save it at Slide.com. As I mentioned, this is not John Q Public's MySpace slideshow of the family trip to the Yukon, featuring "Because of You" by Kelly Clarkson. It only feels that way. In reality, it is "Slide.com presents John's slideshow and Kelly Clarkson."
Slide ultimately retains control of the brand presence, creative assets, advertising, functionality and everything else through the life of that widget, and the tens of millions of others just like it.
If you're currently creating Flash banner ad campaigns, you're really not that far away from having your own widget network. The only missing pieces are the overarching Flash framework to "do it yourself," and a user administration structure for registration and serving the individual widgets. Of course, this is an oversimplification, and there are a lot of facets to consider as you build a system like Slide. The point is, you shouldn't be overwhelmed by the prospect of creating a web widget. You're probably already on your way there.

