If you visit http://www.thethingsiwant.com/tag/babys%20room/ it provides the same results as if you vist http://www.thethingsiwant.com/tag/babys_room/ or http://www.thethingsiwant.com/tag/babysroom/ or http://www.thethingsiwant.com/tag/Babys Room/.

If you tag something as "baby room" or as "babyroom" it shows what you typed but it gets normalized in the database. It also stores "baby" and "room" with a different level (I'm not showing that yet) in the db.