We think one of the best things about Facebook Platform is that it inspires an ecosystem of developers to build creative and timely applications that provide users with social experiences around the things that matter to them most. Likewise, by interacting with friends through meaningful applications, users help contribute to the success of countless developers who are building businesses in this ecosystem.

As we all tune in to watch the World Series, it is an especially exciting time for the developers of baseball applications – particularly those focused on the Tampa Bay Rays and Philadelphia Phillies! With sports fans using these engaging and interactive applications, some of the most heated baseball competitions are happening off the field and on Facebook Platform this season.

Through the entire season and post-season, fans have been going head-to-head talking smack, expressing pride for teams on their profiles, and recruiting friends. Thousands of users are connecting with friends and fans from all corners of the country, posting team badges and photos to their profiles, staying updated on news, playing trivia, and discussing games, all with applications built on Facebook Platform.

Hundreds of sports applications have been built on Facebook Platform, including some of the most popular baseball apps from Watercooler, Citizen Sports and Fantasy Moguls – all of which are seeing growth by drawing in World Series fanatics.

Just this week, since the start of the World Series games, Watercooler’s Philadelphia Phillies application has increased its membership by 20%, boasting more than 62,000 users. Its Tampa Bay Rays application has also seen an increase in numbers, with a 40% jump to more than 11,000 users. Since the start of the playoffs, engagement with Watercooler’s Phillies app is up 175%, while its Rays app is up 150%. Through their FanSection, Watercooler also features a “Biggest Fan Photo” contest that has already received over 2,350 entries so far!

Users are also connecting on Citizen Sports’ Phillies Phanatics and Rays Republic applications, where they can cheer for their team, share baseball news from around the Web, and chat with like-minded fans. The apps saw a 300% increase in visitors and engagement during the first three weeks of October, leading up to the World Series. Citizen Sports’ Phillies Phanatics application currently boasts over 15,000 monthly active users, while the Rays Republic app has over 1,200.

Nearly 153,000 monthly active users are engaging with leading applications to get involved in the World Series this year, with Phillies fans having the strongest presence on Facebook. No matter which team you’re rooting for, be sure to join them if you haven’t already!

And with Football season kicking off, don’t forget to check out Watercooler’s team apps, or Citizen Sports’ Fantasy Football app – with over 97,000 monthly active users. Playoffs are just around the corner, so if you have a great idea for a football-themed application, now’s the time to get it up and running!