What is in a cookie
A cookie contains a list with key-value items called 'name' and 'value'. An item in a cookie could have the name 'email' and the value 'email@example.com'. A second item could have the name 'visits' and value '3'.
Session and persistent cookies
Like with real cookies they come in different flavours. There are session cookies and persistent cookies. Session cookies are created temporarily while you are visiting a website. When you leave the website the session cookies will be deleted. Persistent cookies remain for a period of time and are activated again once you visit the website again.
Who can access a cookie
By default the information that is in a cookie can only be accessed by the 'root domain'. The 'root domain' was set when the cookie was created. This means that all cookies set by ultrablock.org can be only be accessed by ultrablock.org. Sub domains like blog.ultrablock.org or help.ultrablock.org can also access the cookies. Other websites like google.com or facebook.com can not access these cookies.
First-party and third-party cookies
There are first-party cookies and third-party cookies. First-party cookies are set by the website you're visiting. Third-party cookies are cookies that are set by a websites with another domain name then the one you are visiting. These are from websites that offer functionality that is used by the website you're visiting. For example Facebook, Twitter and LinkedIn set cookies via all websites that have their services embedded in their website.
Third-party cookies allow advertisers to build up profiles of users without their consent or knowledge. This is why many people see third-party cookies as an invasion of privacy. All major browsers (Chrome, FireFox and Internet Explorer) allow third-party cookies. To increase your privacy and security Ultrablock automatically deletes all third-party cookies.