Great question; this is something I often wonder when seeing unusual names on HubPages.
Mine was created many years ago when I was going to be a writer for my brother's fiction-based website. I was the sole content provider and I needed something that would guard me from failure. I went through a number of pen names I didn't like until arriving at M. T. Dremer. The last part (Dremer) is actually two sets of initials combined 'DRE' is short for Dr Evil which was my online gaming name around the time Austin Powers was popular, and 'MER' which is my real life initials. When thinking of what letters would come before 'Dremer' I noticed that it was one letter away from 'Dreamer' so the rest just fell into place. M. T. Dremer basically means "Mitch, The Dreamer". It seems overly-complicated and possibly cheesy, but I've loved it since it was created.
When my brother's website closed down I attempted a few online writing-for-money websites, using the name, before finally settling on HubPages as my number one.