Contextual links are links deep from the content of your webpage and that content is the core part which decides the uniqueness of a webpage. Hence, giving links from that section transfer optimal page power to linked ones.
I believe focusing on link building in the international community is a sound idea. I recently started a "link-building campaign" in the UK and by recently I mean last week. Subsequently, there hasnt been enough time to see if there have been any benefits from the link-building I have done, but I still think making connections with legitimate clients in the international internet community can only lead to more traffic on my site and better SEO placement.