Google AdSense is spreading further in Eastern Europe, opening up new money making opportunities for publishers who run sites in the Bulgarian and Serbian languages.

From the Inside AdSense Google Groups :

Two more languages — Bulgarian and Serbian — have just joined the AdSense for content family, and AdSense for search has also launched in Serbian. We know that web publishers in these regions have been waiting for for a long time — thank you for your continued patience.To get started with AdSense for content or AdSense for search, log in to your account and follow the wizard located under the AdSense Setup tab.

Google AdSense has been available in Bulgaria and Serbia, but not in conjunction with monitoring and serving ads relevant to the native language content available on pages.

This makes me wonder, how many other languages does Google AdSense currently not support? And would investment in popular sites in such languages before they find the magic of Google AdSense be a smart business plan?