How safe is Gmail?

I am beginning to wonder how safe Gmail is? I feel that the keywords in emails are scanned and stored somewhere in Gmail database. Something that really bothers me in Gmail are:

1. Webclips: Webclips are enabled by default and it gets news (sometimes) based on the email that is opened or with some keywords in my email.

2. Targeted ads on right side. These are always based on emails.

I believe Google calls this as “Personalized Ad/news service”, but not sure if if my privacy is going out of the window.

Of course I can always go out of Gmail but i use it because of its simplicity. but was just worried about the privacy issues.