bwnbwn - 4:40 pm on Jan 5, 2011 (gmt 0)

Big question on this one

However, 100 people a month click the adword, costing us money

are you making money from the 100 clicks? That is the answer that has to be yes if not why spend.

I could try stopping the adword, and see what happens?

Yes runa test. test test test always test. you could stop it then make a new add to test conversion rates go up or down. Test Test Test.

Or I could continue efforts to get the natural listing higher.

This is something you should always be trying to do.