While they may be old-school to you, Twitter, Facebook and YouTube have rekindled my excitement about social networks. Why? Because they’re finally becoming big in Japan where I make my living as a music marketing consultant.

There are well-established homegrown social networks in Japan that have interesting qualities. There’s Amoeba, the blogging service; Mixi, Japan’s largest social media site; social gaming sites like Gree; and Mobage Town, Japan’s answer to YouTube. But it’s the growth of the American properties that has breathed new life into social networking amongst Japanese. Facebook, for example, has more than doubled its user-base since last fall to 3.7 million actives, but still well behind Mixi’s 23 million. It’s refusal to permit users to use nicknames or pseudonyms has been a significant hurdle to adoption by the privacy-conscious Japanese.

The Japanese have always been early adopters of new technologies, which might explain why they took to the local soc-nets. The success of the local properties explains in part why properties like Facebook have struggled despite launching a Japanese-language versions. It took business-side deals by these three companies to finally get traction.

Twitter was first to enter a joint venture, with Japanese media incubator Digital Garage. Together, the companies promoted Twitter as a service for “those in the know”, which fuelled consumer adoption as celebrities and other notable figures began to jump on. Interest in Twitter spiked when Twitter became essential for news during the recent earthquake catastrophe and subsequent nuclear accident. Today, the micro-blog has 10 million users, placing it well ahead of Facebook (a rarity worldwide).

Speaking of Facebook, the social behemoth passed on a joint venture and instead opened a small local office on their own. To drive sales growth, they choose to partner with Dentsu, Japan’s largest advertising firm, granting them exclusive rights to sell Facebook’s premium ads. One can only assume that it’s Dentsu behind the recent higher profile of the site (and Mark Zuckerberg in particular), in the press and in books. The blow-out success “The Social Network” also didn’t hurt.

As for YouTube, the local YouTube team has been aggressively making deals for local content, and engaging Japanese users to encourage more and better quality video uploads.

For those of us dealing with cross-Pacific marketing campaigns, the newfound popularity of these sites presents an opportunity.  Local soc-nets have a dark side for us: they are known for curbing marketing that is “unauthorized” (campaigns that aren’t orchestrated locally with the company that owns the social media site) and have long been suspected of manipulating results to make the campaigns they help you execute appear more successful than they actually are (and they share very little useful or verified data). So privacy concerns aside, the openness of the American services with their user-friendly interfaces, policies, data-sharing and API access stands in joyously stark contrast to the local soc-nets.

Net-marketers hoping to reach Japanese consumers now have an unprecedented opportunity. For the first time, they can run multiple-language campaigns that include Japan using readily available tools (like Facebook’s Ad Marketplace), a native speaker and a little bit of cultural insight.

Now if only China would allow Facebook and Twitter!