Most often when you download a huge file from a P2P network, it is compressed in the .daa format. When you click on it, you will find that there is no application in Ubuntu that can handle it.
If you are wondering, DAA (Direct-Access-Archive) is actually a proprietary file format created by PowerISO to compress, password protect and to split a huge file to multiple volumes. To decompress a .daa file, you have to use the PowerISO application.
Download PowerISO for Linux
Extract the tar file
sudo tar -xf [path-to-poweriso-tar-file]
To extract .daa file
poweriso extract /input-file.daa / -od /extracted-file-path