The Google Adsense referral program is expanding even more and you can now earn $5 per referral for Google Apps. I have started promoting the Adsense referrals seriously after my surprise $250 bonus. This provides another opportunity to make more money quickly.
Google Apps provides simple, powerful communication and collaboration tools for your organization. Give your users Gmail, Google Calendar and Google Talk accounts that use your own custom domain, Docs & Spreadsheets lets users share files and collaborate in real-time, and it’s all hosted by Google, so there’s no hardware or software to install or download, and minimal setup and maintenance.
You will be credited $5 when someone clicks the referral ad from your site and signs up for Google Apps with a domain that has not already been signed up for the service. That person’s domain must then have one or more Google Apps email accounts in use for four consecutive weeks.
I do not see it in my Adsense Setup Account so it seems to be a US only feature like the earlier Google Checkout Referrals.