To Share or not to Share?

It is so difficult to find resources to use when teaching. Maybe these are some of the reasons we do not share them as teachers...

1. I don't have time to check the online site since I'm too buy creating materials.
2. My stuff is not good enough to share.
3. I don't want anyone else using my great writing technique.
4. I've heard that blogs and other collaborative programs like that have porn so I'm staying away from them.
5. Other subject area teachers don't teach like I do so their materials or ideas won't help me.
6. I've used the same materials for the last 20 years and I won't change now.
7. I have all the transparencies I need.
8. Once I close the door, it is my private world.
9. I am an expert in my subject area.
10. My students like to listen to me lecture each period.

I am sure I have something to learn from this list.