I have been meaning to ask this for sometime now, How many adsense ads can you include on your website before you break TOS? Do they have to be different types in order to work?
yes, it depends on the size and type your are using. They will only display the corect amolunt if you do go over though.
Do you have to use different adsense accounts in order to display 2 ads? I keep trying to display 2 adsense ads and it doesn't show one of them. Am i doing something wrong?
From the adsense blog... We say: Yes, on each page of your site AdSense is now able to support up to: 3 ad units 2 AdSense for search boxes 1 link unit 1 referral button per product (i.e., 1 AdSense referral button and 1 Firefox plus Google Toolbar referral button).
Yes, this is normal. With expanded text ads, AdSense technology automatically displays fewer ads when we determine that larger ads will perform better on a particular page. This should improve monetization for you. Also there may be limited advertisers in the niche you are working. I would let it sit as adsense with index your pages and find more ads over time.