The use of a pen name may not seem like a marketing issue for authors, but it really is. I have worked with authors who have used pen names, and I have always found it to be a big barrier when it comes to effectively marketing their book.
The reason for this is simple: when you are trying to market your book through your platform...friends, family, co-workers, people who enjoy your writing in general...they don't know you by your pen name. They know you as you. If, all of a sudden, you use a completely different name, how will the community members of your platform find you unless you tell them, and doesn't that defeat the purpose of using a pen name in the first place? For example, if you wanted your college alumni newsletter to mention the fact you have published a book, they aren't going to know you by your pen name, and your classmates won't know who you are, either.
Very few of the authors I have spoken to who have decided to use pen names have changed their names for a good reason. They just thought it was something authors were supposed to do. There are times to use a pen name, but they are few and far between.
Using a pen name makes sense if:
1. Your book would cause embarrassment for your friends or family. Perhaps your book is about a very sensitive subject that would bring ridicule or embarrassment to the people in your life, such as substance or sexual abuse.
2. You're in the Witness Protection Program. OK, that might be a little extreme, but if you have a REALLY good reason for keeping your true identity a secret, such as to protect your life, family, job, etc., it might be worth considering a pen name.
3. Your real name is not marketable. You would have to have a name with 13 consonants in a row to really qualify for this one, but if your name is not pronounceable by the average person on the street, you might consider a pen name. Otherwise, the name your parents gave you will work just fine.
4. You want to disguise your gender. This little trick is mostly used by men who write romance novels. For some reason, women prefer to read romances written by other women, not some 50-year-old guy wearing a flannel shirt and smoking cigars.
Stephen King wrote four novels under a pen name, Richard Bachman. It wasn't his idea. At the time, his publisher felt that readers wouldn't purchase more than one novel per year from the same writer. Pearl Grey changed his name to Zane Grey, because he felt readers wouldn't buy a Western novel from a guy named Pearl (he was probably right).
For the most part, the use of a pen name has struck me as being more of a vanity issue than anything...sort of like getting a license plate which spells something cute. It might seem like a good idea at the time, but most people don't get it.
Marketing a book is difficult enough. Why make it harder by disguising your accomplishment of authoring a book?