Does anybody know if Lufthansa offers WiFi services on board the flight from Frankfurt to Chennai (A340)? What are the rates? How good is the WiFi? My requirement is just basic texting, Facebook and photo sharing. Not interested in YouTube or other data hungry applications. I would also be very interested to hear about personal experiences of people using WiFi on this route in particular or other Lufthansa long haul routes.
Haved used it once, Frankfurt to Tokyo in June 2013 (don't remember what kind of plane it was). My usage is mostly the same as yours, and I had no problem with it.
Actually, I had bought 24 hours of wifi access at Frankfurt airport for about 5 euros, and was quite surprised to find that I could also use it on the plane. (If you buy it on the plane, it's 17 euros for 24 hours.) I don't know whether this is still possible, however.
There is a lot of information about this on the Lufthansa website (ie; paid internet on 90% of the long-haul flights) see: http://www.lufthansa.com/us/en/Fly-Net
My personal experience with any airline is that you are better off calling them because they are often dealing with older planes that don't have services like that and they tend to 'forget' to mention this online.
The service mentioned above would be more than sufficient for what you want to accomplish but is not a free service.