Examples of TAPs are electronic programme guides, digital photo viewers and MP3 players.
Anyone with the necessary computer programming skills may create a TAP to meet their needs.
This is possible because Topfield have specified an open (or public) API which allows TAPs to be created using the C or C++ programming languages.
Some people have created TAPs and made them available for others to download and use, either free of charge or for a small fee.
There are several internet forums dedicated to TAPs where information and support can be exchanged.