App stores typically take the form of an online store, where users can browse through these different app categories, view information about each app (such as reviews or ratings), and acquire the app (including app purchase, if necessary – many apps are offered at no cost). The selected app is offered as an automatic download, after which the app installs. Some app stores may also include a system to automatically remove an installed program from devices under certain conditions, with the goal of protecting the user against malicious software.[2]