What do the red and blue lines in a wireframe mean?

I am very new to blender and 3d in general, and have been going through some tutorials, and slowing picking up the basics.

I am trying to figure out how to mark seems so I can UV unwrapp and texture. I am making some progress, although it is not coming out exactly how I expected.

Regardless, my wireframe has gotten in a state where I have a bunch of red and blue lines:

http://i.imgur.com/NJ74nBN.png

I think the blue ones are the seams, although they stay there even if I remove the seams. (How can you remove them)

Anyone know what the red and blue lines indicate? Thanks in advanced for any help.

Turn on/off each edge marking in the Display settings t check which is which