If you have been at FOSS.IN last year, you would have noticed that the participation level this year is significantly less. This is intentional, as per Atul Chitnis (FOSS.IN organizer). This year, the emphasis is more on "workouts" where you can actually code, rather than sit through several lectures or demos. You learn more by coding and participating. Atul mentioned in his inaugural note that less crowd actually meant people could interact and network more. In turn this means, people can learn more from each other rather than from a lecture.
The success of FOSS.IN is not going to be measured in terms of how many people attended, but how much code we are able to create in the next five days.