FrostWire Basic and FrostWire Plus are based on the same code, but FrostWire Plus has the ability to download from YouTube and SoundCloud in addition to the BitTorrent Network.
As of April 2015, we were told we have to remove YouTube from the list of our search engines and download sources to comply with Google Play Rules. If we wouldn't, we would no longer be able to be listed on Google Play. Shortly after, we were told to remove SoundCloud as well.
Because of a great user outcry, we choose to keep distributing FrostWire on Google Play and remove YouTube & SoundCloud entirely, effectively making the FrostWire Basic a BitTorrent Client only, but provide the more advanced users with an option use the fully featured, yet still free FrostWire Plus version.
Anybody can now download the FrostWire Plus version with YouTube & SoundCloud Search and Download functionality + the recently added PREVIEW feature from FrostWire's website free: http://www.frostwire.com/android