The basic blue icon means that the lyrics for that song was filtered, ie. it was downloaded from a known lyrics site. 99,9% of your lyrics marked with this symbol will be the right one.
The grayed icon means that the lyrics for that song wasn't found in any known lyrics site, but EvilLyrics was able to find it (or something related to it) in another site. There is a bigger change of these lyrics be the wrong ones, but there are many times that these lyrics will be one you were looking for.
The blue icon with a speaker is the best one: it means that you already have the timestamps downloaded for that song, so EvilLyrics can show you each line of the lyrics in the right time it is being sung. Note that this icons doesn't mean that the timestamps are available on the server. Much more songs already has timestamps on our servers. This icons shows that the timestamps are already downloaded in your pc.