System Memory Questions

Can you guys give me a better understanding of how this works, here is a screen shot. and i want to say wow with how much memory safari uses. But what i don't understand, I have 4 gigs. what is wired and inactive, wired isnt' taking much memory but inactive is. can someone please explain all this for me? thanks

This should help:

Mac OS X: Reading system memory usage in Activity Monitor

- Nick

Activity Monitor is blank

I don't know if this is the correct place to post this but I hope someone can help. My Mac (Quad Core Intel Xeon with 6GB) is very sluggish. I open Activity monitor and it shows that CPU usage for User is 75% and for System it is 22%. However the Activity Monitor screen is blank. I have no idea what processes are running. Any ideas what is going on? Thanks for your help.
PeterD