I know very little about this woman. She lives in Minneapolis, and she has a very pretty website. Her books Truth or Dairy and Wurst Case Scenario are fun stuff--the rambling journals of a self-absorbed Midwestern teenager with the unfortunate name of Courtney Von Dragen Smith and the willpower of processed cheese. She has also written an uneven-but-very-enjoyable standalone novel called Frozen Rodeo. While the blurb at the back of Truth or Dairy says that Ms. Clark has written several books for young readers, her site only mentions a few of them. (I suspect that's because her other books are adaptations of popular TV shows, but maybe that's another Catherine Clark...?)
Aftertaste: None. These books are a lot of fun. They may not reach the level of crazed humor of say, The Princess Diaries, but they're still really good. Very similar in spirit to Megan McCafferty's Jessica Darling books.