Google AdSense
Discussion
No you can't block competition unfortunately. What may be appropriate and which may differenciate you a bit is to sign up for Google's "local business" advertising service. E.g. go to Google.co.uk site, type in "restaurant reading" and at the top you find a few listings for local restaurants. Not too many people use this yet and the best thing is - it's free! Obviously it's not appropriate for everyone.
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