This is a really useful iTunes 101 lesson for beginners and expert users alike. While iTunes makes it easy to remove duplicates in your song library, sometimes just because a few titles have the same name doesn't mean that they are the exact same song. Because of this, it could take you a really long time to go through checking all your songs to make sure you are truly deleting duplicates and not songs that just happen to have the same name. Thankfully, a reader over at Lifehacker found a way to narrow down your search for duplicates to exact matches only, courtesy of the oft-used Option key. By holding down Option while navigating to File > Display Duplicates in iTunes, the "Display Duplicates" choice changes to "Display Exact Duplicates," thus enabling you to carefully delete only those songs which are exact matches and not just in title alone.
This couldn't come at a better time for me, as I have recently finished loading every CD I own into iTunes, leaving me with some titles that match in name only. For example, I have a ton of bootleg and underground Led Zeppelin songs on my computer. While all songs titled "Black Dog" are by Led Zeppelin, there are different versions from different concerts and old recordings. Without using the Option key to search for them, iTunes might have thought they were all the same, and I might have deleted them if I wasn't paying close attention.
If you have a similar situation in your music library, you may want to give this tip a shot. I certainly am glad I know it's there now!