first question is about the adword vouchers which are being sold out here/ can i use 2 or 3 adword vouchers in my one adword account. i listened that when we activate first time google adword with our credit card google itself sends 100 us dollars credit of adword. so if i have that credit already and add another voucher code(purchased from dp). will it add the both sums and making it 200 dollars credit. or should it first finish the first one hundred dollar creidt. thanks in advance.
Well, you can add only one voucher in your account. Never heard that you will get $100 for adding CC. If you got it in email then may be they are giving it. But if that is used by you then you can't use any other voucher.
If you were Google, would you let an advertiser use as many vouchers as they could, potentially advertising for free ad infinitum? Never heard of this $100 extra when starting an account, except of course using a $100 voucher/coupon. You may just be confusing the two. Google will want a credit card before making your account active, even with a voucher. This is for security reasons and of course to start charging you once your free money runs out.
As far as i know and had experienced, free coupon provided by google can only be used when one creates a new account on Google Adwords and you need to provide your credit card details in the begining to activate the account and start the account as the Coupon amount will be just an additional free amount which will be added to your monthly spend that you wish to spend on Adwords promotion. One cannot activate the account on the basis of Free coupon amount
There is nothing to keep you from opening multiple accounts. Supposedly its against the TOS, but an ad agency might use several companies accounts to place their adwords. My experience is that as long as you use different email addresses and different credit cards, they don't know or seem to care. Use a different coupon with each account.
There are some steps that are needed to be taken as far as Adwords is concerned to improve quality score.