Pen names have been a part of writing for centuries, just as professionalism. Both pen names and professionalism play an important role in internet writing today. With all of the safety concerns involved with the internet, using a pen name is probably a good idea. However, when you choose a pen name, you must maintain the highest level of professionalism - as with every aspect of your internet writing.
Choosing a pen name is much like naming a baby. It will go with you for your entire internet writing career. It will set the tone for how you and your work are perceived by readers and clients alike. You pen name will open or close doors for you as an internet writer.
When you choose a pen name, think like a "real world writer." Your authority as a writer may hinge on your pen name. Would you go to your local bookstore or library and ask for a book about wedding planning written by ClownCollegeGrad1992? Would you consider seeking advice about roses from Buddy Boy? Neither one of those names are professional. They do not demand the respect of your readers and they do not help you sound like an authority on most subjects.
When you choose a pen name, you should choose one and stick with it. Having several different pen names will only complicate branding yourself and your work. It can make promoting your work extremely difficult. Keeping track of "who you are" and your writing style for the different pen names is a waste of time, energy and effort.
You should also consider your readers and your fans when you choose a pen name. How will they be able to find all of your work when you use different names? Will they understand why you use different names? Will they be able to trust you as an internet writer if they learn you use different names?
Once you have narrowed your choices for pen names down to a few, google those names. You will want a pen name that isn't overly used on the internet. When I first started my internet writing career I was writing as Emma Sutton. Several months later, I searched my name and learned there was an English actress with the same name. I knew I wouldn't make it to the first page of search engines competing against her. I added my middle name, Riley, to all of my work and VIOLA! I was no longer competing with an award-winning actress. When you search my name, you will find pages and pages of my work with only limited interruptions by others with my name or a similar name.
If you have already been using several pen names, there is little you can do to change that. If you write for several different niches, it may work for you. I don't recommend it, but it is possible to make it work. You may want to consider choosing one pen name and using it. It will make your internet writing career much simpler.
Your pen name is an important part of you and your internet writing career. Choose carefully, making sure your pen name is professional and will demand the respect you deserve as an internet writer. And, as with all things pertaining to internet writing, have a little fun with it. There is no reason your internet writing career has to be dull or boring.