I Tunes
What the heck does this mean on my Ipod?? Half my music won't play.
The dotted circle with greyed out text means that the song is not yet copied onto your iPod. If the Sync is still in progress, that's why those songs are not yet on the iPod.
Once the Sync has completed if those songs (or some of them) still show as greyed out and with the dotted circle, the title may show up on the iPod but they won't play. This is a bug and there have been issues recently with erratic syncing. We have to wait for Apple to figure out what the problem is and fix it.
In the meantime, the popular suggestion is to try a further Sync, or two. It happens to me as well, but with the last Sync I did between iTunes and my iPod, I reduced the number of songs that were added to it and I think that they have all been added. The Recently Added music has certainly made it to my iPod - at last!
There is a thread about erratic syncing but I cannot find it at the moment. Sorry that I can't be more positive.