I'm at work right now and looking on deepbit and I've noticed that my average hash rate has been like 290-320 when it normally runs 380-410. I'm new to this so is there any reason you would see a decline in your hash rate outside of your computer? Assume my computer doesn't have any new processes running or anything else resource intensive has changed (to my knowledge this is true). Is there something simply to do with pooled mining, or the bitcoin network in general that would cause this?
The speed you see on the website is a calculation, your miners do not tell the server how fast they are working. The server makes a best guess calculation according to the number of shares you submit. Sometimes it's higher, and sometimes it's lower depending on how many you submit between calculations. 100 is not out of normal boundaries. As long as it's not dropping to 0 you're ok.
Please excuse the less than helpful troll comments.