Creative Commons and Copyright

I feel like it is strange that we have just now discussed copyright at this point in the course.  It is obvious to me that it is an issue that needs to be considered in the context of any web2.0 technology.  In fact I was concerned about it when I made my PLN visualization as I was looking for images that were in line with my ideas about my personal learning network and the pictures I selected.  To be honest after reading all the information I feel both more concerned and more confused about how to decide what I can include in the products for this class and for my own classes.  The four factors that decide fair use that were cited repeatedly in the readings/podcasts are so vague that it seems as though one can construct an argument for almost any "fair" use of copyrighted material that is not overtly stealing.  Even as I write this I am aware that what it means to overtly steal content is my own construct and may not be agreed upon. 
The Creative Commons copyright is a wonderful idea in theory.  However, when I tried to use the link to the creative commons search provided in the lab I was dismayed to find the declaimer in a link on the site stating that
"search.creativecommons.org is not a search engine, but rather offers convenient access to search services provided by other independent organizations. CC has no control over the results that are returned. Do not assume that the results displayed in this search portal are under a CC license. You should always verify that the work is actually under a CC license by following the link. Since there is no registration to use a CC license, CC has no way to determine what has and hasn't been placed under the terms of a CC license. If you are in doubt you should contact the copyright holder directly, or try to contact the site where you found the content."
So the resource that is meant to ensure that I don't infringe on a copyright can't ensure that I don't infringe on a copyright?????  What good does this do us then?  Where do I find the statement that tells me exactly what the "CC" is?  Is it always obviously displayed?

Ahhh math humor, maybe this will lighten the mood.  Requires understanding of Complex Analysis though. :(

"Graffiti math"
by Quinn Dombrowski
http://www.flickr.com/photos/quinnanya/

Released under Attribution-ShareAlike 2.0 Generic (CC BY-SA 2.0)

My image.  Experimental Probability Lab in Algebra 2 Honors, during my internship year.

MAET

https://picasaweb.google.com/slawatsch/MAET?feat=directlink

I use images and video all the time in my class I am worried at this point that I am not using them appropriately.  It was nearly impossible to find images that resemble the things I use on a regular basis.  Advanced math seems to make this difficult.  This lab has made me significantly more concerned about using any images.  I hardly have time to plan effective lessons and I certainly don't have time to spend digging through licenses on the web for two hours before I use an image.  When I show an image or a video in a class it is always for educational purposes, I have no idea if this passes the test for copyright infringement but i do know that students have learned a lot from my choices.  I think I would have enough of an argument that I have transformed the content into an educational experience that I am alright but I also want to respect intellectual property in the same way i would want others to respect my own.