Over the past couple of months, I’ve noticed an unusually large increase in the number of my friends and former colleagues based in the UK that are joining Facebook.  The recent surge in popularity of Facebook among my UK friends has me wondering: What lit a fire under so many people in non-overlapping networks to join Facebook at around the same time?  Is it a fluke, or is the flurry of activity the product of something else?  A particular marketing campaign? Increased mentions in the UK press?  Unusually fast spread via word of mouth?  The announcement of new developer network?

From the outside, I can’t point to a particular cause, but one thing is for sure… Facebook newbies are joining at the right time, as the site continues to get a whole lot cooler thanks to the addition of 3rd party applications to Facebook.com.  The economy of 3rd party Facebook applications is now booming.  Developers are going wild, and as a result, Facebook is becoming a much more interesting place to spend time online.

Opening up the Facebook platform was a GREAT move for several reasons:

1. Creating a 3rd party developer network will bring a whole new segment of users to Facebook – developers and those in their networks.
2. The availability of a larger number of applications gives users more reasons to spend time logged on, which in turn increases Facebook’s attractiveness to both users and advertisers.
3. It creates an economy upon which a larger number of people can benefit.  With Facebook, 3rd party developers have a place to be creative and market their products to a wide and connected audience, without the financial risk associated with going to market on their own.  Facebook users are closely connected to each other, and as a result, good applications have a much greater chance of succeeding quickly through viral marketing.

Companies like Apple, Microsoft, Palm, and others have been benefiting from their investment in Developer Relations for many years.  In most cases, opening up their platforms to developers and independent software vendors (ISVs) increases interest in the said platform, boosts usage scenarios, and generates buzz among press.  In my experience (managing global partnerships with with Windows Mobile Developers for Palm, Inc. for the Treo 700w and Treo 750v launches), besides users, 3rd party developers are some of the best evangelists a company can get.  They’re passionate, fiercely loyal, and incredibly vocal.  When a company invests in Developer Relations/ Partner Alliances, giving developers all of the tools/ documentation/ support they require to innovate and profit from development, the results far outweigh the costs.  In sharp contract, when a company doesn’t invest significantly enough in 3rd party developers or invests in a program that lacks direction or doesn’t provide developers with the basic tools, information, and sales/ marketing channels they need, the results can be disastrous.

So far, it appears that Facebook is doing a great job providing developers with the tools they need.  And, as a result, the market for 3rd party Facebook applications is booming.  A couple of my friends recently developed a Facebook app and based on their experience, development of a Facebook app is easy.  It’s been fun to hear about the success of the application and share it with my friends.  I’ve also enjoyed browsing the Facebook applications catalog.  I recently added a BBC news feed and an app that let’s me track which US states I’ve visited.  What’s great about the catalog is that you can read reviews of apps before installing them, and it’s quick and easy to remove apps you don’t like.   In the future, I’d love to see a Yelp-style star system of reviewing enabled in future generations of the catalog to users help weed through all the apps before making a selection, but the existing catalog is a great 1st generation starting point.

If you’re interested in developing a Facebook app, check out Softwaredeveloper.com, who just published a very useful article for developers called “How To Develop a Hit Facebook App: 29 Essential Tools and Tutorials.”