Everyone has been, at some other time, with that catchy song stuck in your head for days.
Wouldn't it be awesome to have a Lyric Search Engine that could directly find the song with just those few words you remember ?
And the best of all: AN OPTION TO FILTER AND TO LOOK FOR 'THAT' SONG -ONLY- WITHIN YOUR LIBRARY OR IN A SPECIFIC PLAYLIST.
That option will enable you to get straightforward the song you've been singing for days right away in just a few seconds. And the best is that, if you only search within your playlist those words, you'll get rid of the rest of the songs you know you don't want.
It'll be something like: making easier to look for that needle in the haystack.
When Spotify had the collaboration with Musixmatch there was a similar option to do it but the database was huge, by reducing it only to your songs it'll facilitate the processing and will optimize the results.