There's something to be said for being the first person with your own name to become really famous; you can just keep it and turn it into a trademark. Somehow, we'd made it all the way into the 21st century without the world ever seeing a truly famous Adele, and so when it happened for the British singer of 'Skyfall' and 'Someone Like You', she cut off the rest of her name, kept her real first name, and turned it into a brand.
In full, the multi-award-winning vocalist should properly be called Adele Laurie Blue Adkins, which is quite the mouthful. Of all the real names she had, you'd have suspected that she might have used 'Blue' for at least part of her stage name (Adele Blue has a ring to it, no?), but she may have been put off by the fact that 'Blue' are a popular boyband back at home in the UK.