Just got a $100 free AdWords coupon to tryout. It was in an HP ink cartridge. Question. I have 40 websites. 39 or them are linked on the home page of my main 5 year old index page that has a page rank of #5. All the 39 sites are of different niches though. How best to take advantage of this adwords coupon? What should I do as far as keywords are concerned. Focus it on my 5 year old index page where all these are linked?
I would personally focus on one niche. The more specific traffic you can get to it the better conversions you will get. If you are just getting general traffic to a site with links to different things, your conversions will be far and few.
I'd experiment with the niche you are making the most revenue per visit. Figure out your revenue per visit and make sure you pay less than that per click. Viola! Instant ROI.