Cookies do have benefits. One is that for websites that one frequently visits that require a password, cookies may allow a user to not have to sign in every time. A cookie can also track one's preferences to show them websites that might interest them. Cookies make more websites free to use without any type of payment. Some of these benefits are also seen as negative. For example, one of the most common ways of theft is hackers taking one's username and password that a cookie saves. While many sites are free, they sell their space to advertisers. These ads, which are personalized to one's likes, can sometimes freeze one's computer or cause annoyance. Cookies are mostly harmless except for third-party cookies. These cookies are not made by the website itself but by web banner advertising companies. These third-party cookies are dangerous because they take the same information that regular cookies do, such as browsing habits and frequently visited websites, but then they share this information with other companies.