After a few days I received 4 or 5 calls from different locations and phone number stating I have filled in a coupon in super market and have won a gift. To get the gift I need to come to particular location and attend a presentation. When I enquired, they said its regarding a MLM Business. Later I realized my information was shared / sold to some third party companies, who are trying to market their products.
This is no big surprise to me, because I know well that leading mobile companies, sell our data for a good cost/value to the marketing agencies and companies, who frequently use to call and SMS (Text Message) us in a regular basis to sell some product or service. In countries like india, though we opt out for a DND / DNC (Do Not Disturb / Do Not Call) we receive even more calls as the rules are strictly not followed, or before we opted itself or either the data is already with third parties. That goes one side, but on the other hand, they online survey mailers and website, they too have started getting our data from us for their business and for the growth of other business ;)
Between, you can trust some corporate companies, who ask for subscribing to newsletters if you unsubscribe and even you can provide confidential details if you are purchasing a product or opting for service. They tend to use these details only to remind you if the service/product is going to expire or update you some special offer if required. But this also if you wish they will provide, if you don�t they won�t. So your data is in safe hands. If you happen to register with some miscellaneous website, probably your data is No-More Safe. THINK & ACT.
After making this analysis, probably I will have to change my mobile number - so that I don't get irritated / frustrated with dump calls. :)
Don't forget to look in to this link - a guy frustrated with kotak mahindra bank marketing call, has shared the real experience.