Why is Google Toolbar bundled with everything?
That is correct. Any of the items in the Google Pack pays $2 per install. From the Google AdSense Referrals page… “Give your users the power of Google on their desktop PCs. Google Pack provides a single installer for many essential PC applications from Google and other trusted partners. These applications improve your browsing with increased speed and security, provide better searching capability for the web and for your own PC and enable you to collect and organize your personal data, including photos. Visit the Google Pack website. Google Pack referrals will only be visible to users located in certain countries. A Firefox referral button will be displayed to all other users. When a user downloads and installs at least one component of Google Pack through your referral, we’ll credit your account with up to $2.00” This is a bit different from the contract with Skype and Adobe, but it’s the same premise.
Google Toolbar is included in other software installs because Google pays those companies to bundle it. This kind of bundling is pretty common; eBay and Yahoo both do it for their toolbars, too. They all do it because they make ad revenue off of the toolbar users. I’m not wild about the bundling either, but at least the Google, Yahoo, and eBay toolbars are somewhat useful and behave ethically. A few years ago it was popular to have sleazy advertising spyware bundled with apps, in some cases stuff that was criminally deceitful and impossible to uninstall. That seems to be dying down now. Note that the linked ratesheet is but one possible arrangement. Big bundling deals like Skype or Acrobat Reader are presumably negotiated separately.