Some advice for posting your lyrics and songs demo or completed. get them copyrighted http://www.copyright.gov/
Since you have your original lyrics with you and the ones posted were timestamped as Mahmoud stated, you should be fine.
A lot of people don't realize once you collect your work in a tangible form (written on paper or recorded and time stamped in some way) they're already copywritten for all intents and purposes.
If someone were to infringe on your work and distribute, release or copy without your consent you'd still be covered but you'd have to go through all the hoops to prove it's yours.
By copyrighiting your works... when someone infringes all you have to do is pull out your documentation.
It's pretty easy to do as well... from what I remember if you submit your work on media (cd or dvd) it costs something like $45.00 to protect the contents of the entire disc.