There are at least three artists using the name You Know Who:

1. A Scandirock & Roll band from Stavanger,Norway.

2. You Know Who (also written YouKnowWho) is a Danish dance act consisting of Christina J. Undhjem, Martin M. Larsson, and Lars H. Jensen.
They recorded some hits like "Guantanemera", "Good And Evil" and the album "You Know Who".

3. A punk rock trio based in the Southern California desert, fronted by Mike Pygmie, also of Mondo Generator. Read more on Last.fm. User-contributed text is available under the Creative Commons By-SA License; additional terms may apply.