Colour stars are a variation of Hatena stars that you can use to express your feelings about something you like. There are green, red, blue and other rare types of colour stars. You can buy a 'Colour Star Box', and depending on the type of box that you purchase you might get lucky and receive some rare stars! You can earn colour stars for your activities on Hatena's online services or purchase them. Add colour stars to entries that you like as a gift, or just to add some colour and call attention to the things that you like.