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.
"Signal Fire" allows you to share your current location with your friends simply. You can search your location and modify it. You can send map URL or map image URL via email. You can post map URL to Twitter.