Jaksta uses a music fingerprinting service to find the name, artist and album of a given track.
This fingerprinting service is very accurate and uses a chunk of the track to figure out which one it is.
Sometimes the lookup service won't return a result. This will be when it cannot be found in the music database.
In this case the song title, artist and album will be left blank. Unnamed tracks will not be automatically sent to iTunes. It works this way so that you don't end up with a bunch of unnamed tracks in your music library.
You can easily enter the details manually, then Send to iTunes manually.