Is anyone interested at all in reaching the Hindi speakers? I personally think that it is a market ready to explode considering that almost all the upper-middle class Indians that are bilingual are already on the web and the new wave of users is those that speak Hindi and other Indian languages.
Hindi is a PITA to read. Most public schools teach it till the class 10th and then drop it unless it is elective. Most people, ( middle - upper middle class) likely to have an internet connection, can speak in Hindi but would rather read in English..
Hindi would reach out to the Northern heartand of India - Uttar Pradesh/ Parts of Bihar/ Jharkand/Delhi/ Some parts of Punjab and Rajasthan and Haryana.. Really people who are yet to graduate to heavy internet usage..Not really a market for online sales, i would think.. Still a while to go. I would give it another 5- 7 years.
I also read that just 3% of Indian people are bilingual -- that makes it about 30 million people.
So could it be that many people who like to access the web in English are doing so because content in Hindi is simply not available online.
But there are students etc looking for specific web content in Hindi.. example famous Hindi poems, essays etc But they are few and far between.
Suffice it to say that a person who knows only Hindi cannot access web easily ( accessibility problems.. all literature and software is in English, Browsers require English knowledge etc) and a bilingual person would rather work in English.
The millions you mention are in the North of India and maybe a potential market. But I don't see it exploding anytime soon.