WP Themes Plugin allow us to preview a theme without activating it from admin panel. This plugin is great for sites that offers WordPress themes but can be used by anyone need to see how a theme looks on his site without making it visible to everyone who visits the site. WP Themes Plugin can help you to check if a theme have errors before activating it for all visitors. Also with this plugin you can show your visitors how your website looks with other themes and maybe leave then to vote what theme they like.