Use of cell phones in India

Today only I read a news item saying 10-20% of cell-phone usage in India is for 'missed-call's. 'Missed-call' has become such a common day-2-day term that it should be added in an english dictionary.

missed-call; noun: an action by a cell-phone caller where he/she drops the call only after 1-2 rings. Mainly used to indicate to the recipient about caller's interest or presence. A 'coded' call which is free.

When I visited India last, it took me a while to understand the real 'meaning' of missed-call. No wonder, even in US, I get missed calls from India and I am supposed to recollect the caller's identity from the number and call them back.

Common usage of missed-call:
1. Caller wants the recipient to call him back at recipient's convenience.
2. Caller thinks it is less expensive for recipient to call-back. A hang-over from last decade when cell-phone calls were 'really' expensive.
3. Some people have coded missed-calls. like "1 missed-call=call-back whenever get time", "2 missed-calls = call-back urgently", "3 missed-calls = call at some specific number like home/office/cell etc/". Similarly other missed-call frequencies can be agreed upon and encoded.
4. Missed-calls are also used as reminder or morning wake-up alarm. For instance, people decide in advance that a missed-call in the morning means he is ready for pre-decided task/job.
5. A regular evening missed-call to home-maker wife: husband is reaching home in 5 minutes, hence get the tea ready. :-)

Any other usage you can think of or came accross?