Gmail is very safe if you know exactly how to use it.
Here is some important Gmail tips:
Gmail offers secure connections "https" when you initially log on and enter your password, but sometimes even though when you log in, Gmail forces the authentication over SSL, you are not secure because it reverts back to a regular unencrypted "http" connection after the authentication is done. If you sign in to Gmail via a non-secure Internet connection, like a public wireless or non-encrypted network, your Gmail account may be more vulnerable to hijacking. There is some Gmail account automatic hacking tools which automatically steals IDs of non-encrypted sessions and breaks into Google Mail accounts. Read about it here: http://news.softpedia.com/news/Gmail-Accou...con-91747.shtml
What to do in order to prevent your data being intercepted by third persons?
It is highly recommended to select the "Always use https" option in Gmail any time your network may be non-secure HTTPS, or Hypertext Transfer Protocol Secure, is a secure protocol that provides authenticated and encrypted communication and using this feature, your connection will be always secure, even when you reading and writing e-mail or you chating via Gmail. To enable this feature in Gmail, you should click on "Settings" in the top-right corner, then on the default "General" tab, scroll to the bottom of the page (Browser connection) and turn ON the radio button to "Always use https" , "Save changes" and reload your Gmail!
How to check if someone already know your Gmail password?
As I know Hotmail and Yahoo mail do absolutely nothing in this regard. Gmail offers an so called "audit trail". When you first log in your Gmail you should scroll down to the bottom of the initial page (Picture #2) and look for a message such as:
Last account activity: 11 minutes ago at this IP (90.191.XX.XX). Details
If you use any email notification tool (e.g Gmail- or WebMail notifer) you'll maybe see something like that:
This account is open in 1 other location at this IP (90.191.XX.XX). Last account activity: 11 minutes ago. Details
If you didn't last log in to your Gmail account when the message indicates, then someone knows your password. Click on "Details" (at the same Last account activity line) and you will see information about the last activity in your Gmail or any other concurrent activity like "This account is open in one other location"
(e.g if you use some Gmail notifer or you FORGOT to log out from your Google account after using a friend's or a public computer). Now you no longer have to worry. Being extra cautious, you can click on the "Sign out all other sessions" button to sign out of the account you left open on other computers (Picture #3).