A common style of self-discouragement I witness in the Internet is the use of adjectives in nicknames that describe one's level (or more accurately, lack) of experience and knowledge. Prefixes/suffixes with "beginner", "newbie", "novice" abound and should be no strange phenomenon to anybody who frequent online communities.
While I believe everybody should be free to call themselves whatever they like, I regard this as an unhealthy mindset and attitude. When you (if you don't practise this, then congratulations) register an account with communities that require membership, your username/nickname is usually permanent. Remember that in the course of human life, everybody changes. Your experience is therefore an ever changing state. By identifying yourself to a lowly state, you convey this message:
I am a newbie and am intending to remain one forever.
Not just to others, but most significantly to yourself. You bind to the ground yourself subconsciously, believing you can never grow to a level of significance. You are crippled on Day One.
Of course, probably most communities and their related domains (e.g. hobbies and side interests) are not very important to you, so you may jolly well remain a greenhorn the rest of your life. That is ok. What does not bode well are communities of industry professionals. If that is to be your chosen career and profession, then how much it speaks on how far you want to go with your job.
PS - this is not endorsement for everybody to use monikers like "dotNetGURU" to mark their ambition. Although "Mr.President" might still sound fine. Oh wait a minute... that may make you look like an idiot....