Tax Deductible?!?!

Quick random question... Seeing as we are essentially contractors working promoting ads or clicks, is the money we spend promoting our pages tax deductible? Specifically, if i pay Facebook to promote my page, could I claim that the purchase was for business purposes and write if off?!

Of course...this is an essential business spend just as petrol is to a taxi driver....and your tax liability is calculated on your profit only.