Hello there and ýu sæló to you.
There isn't much to it, really. Some artists make their lyrics widely available, while others don't. Which eventually causes us listeners to figure them out. At least that is, until something concrete is made available thru their respective official medium. So, until then, people like me will continue to pop, here and there, posting whatever it is they can make out or forward the work already produced by fellow listeners.
Currently I have an eye on the following projects: Amiina, Benni Hemm Hemm, Jónsi, Jónsi And Alex, Múm, Seabear, Sufjan Stevens, Sin Fang Bous,and Sigur Rós.