online privacy, Flash cookies, security
Google introduced encrypted search: https://www.google.com/.
It keeps hackers from knowing what you are searching and results.
If you don't know already, when you use the browser, anything sent and received by your browser is sent in the open. That means, any hacker can trivially listen in. Unless the url is “https”, which means its encrypted (typically the login/password page is https, or banking sites).
This means your facebook, blog, are all sent in the open. Some IM chat such as AOL, MSN, Yahoo offer encryption, but you have to turn it on. Skype skype.com chat is ALWAYS encrypted. (See: Skype Chat Encryption and Screen Sharing.)
Also, if you are worried about privacy, you can turn off cookies in your browser. Or, in your browser start Privacy mode. Though, note that all it does is things like turning off cookies and stop saving browsing history. These are useful if you are in a public computer such as library. But at your own computer at home, it is basically not relevant.
Note that if you use Flash (e.g. youtube, movie sites, games sites), the Flash will store cookies separate from your browser's cookies. Sites with Flash can track you. You can turn it off here: macromedia.com, but it is a pain to do. I really hate Flash. Don't use it if you can.
Also, today there are so many technologies that even if your are a pro web programer, none actually knows well all these techs. For example, html5 and tech on mobile devices, see: http://arstechnica.com/apple/news/2010/09/rldguid-tracking-cookies-in-safari-database-form.ars.