The "Download Now" link directs you to the iTunes App Store, where you must continue the download process. You must have iTunes installed in order to open the link, and you must have an active iTunes account to download the application. This download may not be available in some countries.
From NKR Innovations:
Buzzinga!The new and exciting way to stay in constant contact with your friends, family, team mates...Group administrators:To get started, just create your group and invite friends to join.As the creator you are in control of who is allowed in by using the Buzzinga! approval process.Once approved by you members are free to send and receive messages as well as see where the group members are, using Buzzinga! mapping.Members:Just find the group you'd like to join and send the request to join. Once approved you're ready to start buzzing!Create and be a member of as many Buzzinga! groups as you like, it's free! Joining a group requires an in-app purchase.Broadcast messages for the whole group to see!See where everyone is hangin'!Enjoy Buzzinga!Continued use of GPS running in the background can dramatically decrease battery life.