If you want to save any of the posts that you find on Launchyoo while browsing through the walls and groups, so as to be able to see it at any later time, you can do so quite simply: by accesing the post menu (three horizontal dots icon) and the selecting "Add to Bookmarks".
Next, if you access the Saved page from the icon to the left of your photo, on your profile page, you will see the list of all saved posts, in chronological order of publication. There, you can consult them whenever you want and delete them when they no longer serve you.