-Cookies can store upto 4 GB data.
-It stores the previous data accessed by any visitor.
-Using cookies, we can personalize the user.
-Cookies are maintained at client site. It keeps a data with time for expiry time within time frame. If I access the page, it shows the information accessed last time.
For Example, Shopping site shows a list of items. If a user re-visits the page, then, the page sites over the server should know what user has accessed or chosen in his last visit and can show it in next visit.
That is all possible if we apply the cookies between user and page.
Cookies in asp.net
There is a class (httpcookie class) in asp.net to enable the cookies to personalize the user information/experience.
Properties of httpcookie class is a)Expire b)Value