1. Stylish People : 843,314 members

The community started a couple of years back and is an amalgamation of wannabes and the fashion-conscious.
2. India : ~9,00,000 members

Expected. Pro-India and anti-terrorism communities are very popular with Orkut members.
3. Chocolate : 55,000+ members

There seems to be an abundance of girls and people like Paritosh on Orkut, as the ‘Chocolate’ community is the third most popular with Orkut users.
4. MTV : 31,000+ members

The youth branding, plus the presence of hit shows like Roadies, Splitsvilla and Stunts Mania helps.
Many community owners also use their ‘popular’ communities as a source of income. Advertisers are very easy come to for these communities, but don’t pay as much as they would pay for an American/European community on facebook or myspace. Also, the moderation levels and quality in these communities is very low and works on personal whims and fancies.
Related: How to unbloack Orkut / Myspace / Facebook / Xanga ?