Please help me find out the grammar errors in the paragraph?

[Nicole]

Good morning, ladies and gentlemen. I am Tony and the topic of my presentation today is about the negative aspects of the social networking sites.
I have been using the Internet for more than ten years but I deleted my social networking accounts some years ago because I think that they waste time, leak information, and are very dangerous had my account been stolen.
Before I start, I want to tell you a sad story about me. When I was a senior in high school, I wrote a diary every day on a website named wordpress.com. I recorded what had happened in my life and what ideas I had in my mind. Sometimes I would complain about a person who I dislike. I did not worry about that because nobody knew I had a blog. The life was peaceful until one day my girlfriend typed my name on the search engine. We broke up because she found some diaries and photos about my ex-girlfriend in my blog. I hate social networking and I want to remind you delete anything about your ex when you have a new boy/girlfriend.
OK, now let me start with the first point; wasting time.
A consumer organization found that in March 2011, a typical Facebook user was on the site for a staggering 53 minutes at a time. For the study, the researchers quizzed 219 undergraduates about their study habits and time spent on Facebook. They found that 65% of Facebook users login to their account daily, often checking it several times to see if they had received new messages.
The second point I would like to make is about leaked information. I think the story that I told you before is an good example. Maybe you will say I deserved it, but on the other hand leaking sensitive information is a very seriously problem. In 2010 the police in New Hampshire broke up a robbery that was using Facebook to plan their heists. They collected users' information by Facebook to determine when a target would be out of their home and then robbed it
Next, I would like to bring up the matter of stolen accounts. Can you image how dangerous it would be if your social networking account has been stolen? There is a report from July 2011 called "Hacking on Fox News Twitter Reports Obama's Death". Fox News on Twitter has more than 38,000 followers and after this, Fox News deleted their account on Twitter.
In short, I want to say that social networking sites negatively impact our lives. If you do not want your information leaked, your time wasted, and your accounts stolen, then stay far away from social networks.



There. All better