The chart displays the number of the keyword searches compared to all Google searches (any keywords). It does not show the actual number of searches. What does it mean? We know Internet is growing globally. The number of domains registered is also growing. Knowing that we can draw conclusion that if the trend for .in domains is holding its level on that chart, its popularity is actually growing.
To prove my point, look at the chart for .de and .nl extensions:
Google Trends
You see both graphs are constantly dipping and one would say they lose popularity. Nothing more misleading. Both extensions are very strong and growing steadily. It just means the number of searches is
relatively smaller compared to global searches for any keyword.
Why does it happen?
I see 2 main reasons for that:
1. The number of searches in Asia (especially China, but also India and other raising economies) is growing dramatically.
2. In countries like Germany or The Netherlands where the Internet user saturation is high, any additional usage growth is difficult. They also cannot match the Asian population numbers. The 80 mil Germans is perhaps a big number in Europe, but that's not even enough to match a medium size Indian state.
I find the .in growth is one of the most dynamic compared to other extensions. Perhaps it was slowed down a bit by the end of the promo but it's still growing faster compared to most others.
That growth peaks always happen in April - May only that each next is stronger. Why these months? I think that someone from India will be better to answer this question. It may be something to do with the end of school year.