I have two questions about AdSense.

Firstly, I and a few friends joined AdSence just three days ago. Ater going through the rules, we were left wondering... What is "repeated manual clicking"? What I'm really asking, is how many times can any one person click the ad box per week?

Another question I have is about eCPM. My riend has the same type of AdSense ad, but makes less per click than I do. Why is that? (I feel guilty that mine is beter, and he told me about AdSense!)

The repeated manual clicking thing is to prevent click fraud. There is no reason why you or your staff/friends should click your own ads (other than occasional troubleshooting) unless you are trying to artificially inflate the click rate.

So I guess the answer is don't think in terms of 'how much can I get away with' but rather 'I don't need to do that so it's immaterial.'

we would never do anything against policy of AdSense. We just were wondering what multi-clicking by the visitor constituted. Another concern is how vulnerable AdSense is to those who would purposely sabotage an AdSense account. Any Thoughts? We just want to make sure in any way possible that our accounts are safe, and that we don't lose them.
(I'd like to maintain my account for a much needed console upgrade )

To answer the second question ... it has to do with your industry, the keywords on each specific page of the site (and how much people are willing to bid on those keywords), and the click-thru rate of each of your ad spots. Remember, it's a violation of Google's terms of service to tell others your eCPM, so technically you and your friend shouldn't be comparing. Technicalities!