The second and more relevant change to me is that publishers outside of the three regions listed above, you will not be able to promote Adsense as referrals. When this change takes effect at the end of January, you may still continue to promote referrals for other products listed in your account under "Adsense Setup" -> "Get Ads" -> "Referrals" (see below).
I have been showing referral ads for third-party advertisers using this sort of Adsense ads, and I have to admit they have not been successful at all. Perhaps the conversion criteria of advertisers have never been met as they usually require the visitor to purchase products or signup for services. Thus, I prefer to show Google-related referrals, such as Adsense, AdWords, Google Pack, and Firefox plug Google Toolbar, because their conversion is more attractive and their target audience is more global.
Getting visitors to switch web browsers from Microsoft Internet Explorer to Mozilla Firefox is the most satisfying because I've been a strong advocate of Firefox. If you're not on Firefox, you're missing out on the superior page rendering and extensive functionalities of this open-source browser. Click on the link on the right to download Firefox!
Back to Adsense referrals, unless you have a blog topic related to helping publishers monetizing their sites, I'd recommend you avoid promoting such referrals at all. Google Pack is a good choice as the software pack is very useful for common Internet users.
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