What can I do to stop or delete cookies being installed with the Opera browser?
Opera have arguably, the most flexible and the most specific privacy and cookie control of all browsers.
It allows you options that range from blocking referral websites to deleting cookies at the end of each visit, and to manage cookies for specific websites.
It even allows for rejecting automatic redirection, from a website, although most websites might do that for perfectly good reasons. Disabling automatic redirection can be impractical most times but it does allow that extra control over what sites you visit.
For controlling your preferences for Referrals and control over redirections, Go Settings > Preferences > Advanced > Network
"Send Referrer Information"
If you wish to keep your last website visited secret from your next visited website, uncheck this option.
"Enable Automatic Redirection"
Switching this off will prevent a website redirecting your browser to another website address, which often can be for a valid reason and can happen fairly often as a page or a whole website may have moved address. This is generally only a security risk, if the site has been hacked and redirects you to a malicious site.Having a good security sysytem installed on your computer will minimise any risk.
Enabling Cookies in Opera
The settings have been simplified as Opera now supports site specific preferences.
These allow you to change your cookie settings on a per site basis.
It's as easy as choosing your domain in which you wish to create a site preference for.
Handily, Opera's browser gives you the option of simply clearing the websites and it's third party cookies at the end of your visit. This will not delete any cookies previously installed.
Opera has 5 manageable options for general treatment of cookies. They are Allow all, Prompt to accept, Block all, Block only third party cookies ,and or Delete new cookies at the end of a session. It should be noted that Opera refuses to accept all "invalid cookies" which it defines as "being set for top-level domains: domains ending in .com, .net, and .org, among others. Such cookies are considered invalid or illegal and are blocked because:
:Any Web site could read such a cookie's contents, it would have unlimited access.
:The only use for such cookies is to track surfers across the Web."
Enabling Cookies in Opera 10.0
More information on managing Opera's privacy functions are available here. http://www.opera.com/browser/tutorials/security/privacy/
Stop cookies being installed on other browsers