Some people might not realize this since a lot of us go through the day using our smartphones without even thinking about privacy. Privacy used to be a huge concern but nowadays we have become desensitized to the fact that we are sharing very personal data with these huge corporations like Google and Facebook.
Back when i was doing PHP in degree, i was building a website for my own company. We were building a page to recommend restaurants with the targeted audience is the public users. So, the login needs to be simple and easy, hence, facebook login. What i discovered then was that every time you click a like button, a bit of your information are being shared to the owner of that button. Basically your public profile(name, age, school, interests, whatever you set as public in your fb profile.). Sure its public info, but with a bit of hacking the owner of the button may actually store that information.
That is however irrelevant compared to the degree of information I myself has been feeding Google about my life. I usually write it off to assist Google in determining the valid roads or whatever Google uses the data for as long as i can get to see the data i share as well. Hey Google Now also gives me information about the time it takes to work, or to the cyber cafe depending on the time and my travelling habits. But then, Google actually stores specific location history about where i go everyday, so as I opened the Google Dashboard i freaked out a little. I can see where i was at any time of the day, any day of the month for months since I switched on the location sharing. If my girlfriend breaks into my Google account, she can stalk me where i am and where I’ve been at any time of the day, any day. Shit, that’s scary =P
On a more serious note, sharing things about your personal lives may allow you to have better services from these products, yes, but is it worth giving up any privacy you might have and potentially become another digital sheep in a digital pen? I guess the question is for each person to answer themselves.