One of the interesting frontiers in the market today is the role that widgets and/or Facebook Applications (and soon OpenSocial applications) can play in your overall marketing strategy, and, of course, how this will impact your search marketing strategy.
To dive into this a bit deeper, I spoke recently with the Greg Spector, co-founder of Rebtel. Rebtel offers a great service that allows you to convert phone calls to your international friends into local calls. For example, if you live in San Francisco, and have a friend in Germany that you want to speak to, the system will generate a 415 number for you. You can then call that number, so the phone company sees a local call, and then Rebtel connects you directly with your friend in Germany.
It's a neat service. When they were looking at ways to promote the service, they quickly developed a belief that a Facebook Application would be a great way to go. So they developed a Facebook ap that automatically identifies all your friends that are located internationally, and makes it wasy for you to decide which ones you would like to generate a number for.
In one sense, it's a great enhancement to people search, as now finding one of your friends overseas comes with the extra juice of making it cheap and easy to contact them. In addition, as I have written before, these types of tools have the potential to spread virally. This provides great visibility and exposure, which ultimately is what you need to do to run a business that accumulates links to its web site automatically (which is a form of SEO nirvana).
The key that makes this work is having an application that leverages your business, and still fits neatly into the Facebook environment. Rebtel did this quite nicely with their application, and this is what makes it very interesting.