This extension simply adds a button that allows you to switch between desktop and mobile versions of Twitter. Is it useful? Yes! Sadly enough, there are some differences between the two versions: for example, if you are using the useful Twitter bookmarks on your smartphone (to create a reading list of tweets), you won't be able to access them from your pc! With this extension you will have the best of both worlds. It makes the transition between the two versions as smooth as possible: you will be able to switch from one to the other without changing the current page and if a page is not available on the version you have selected, you will be simply redirected to the home page.