A newbie is a new member of any community, online game or web-based activity. It’s a difficult word in that it’s often hard to tell the sentiment behind its use. In a purely descriptive way, it simply refers to new members, and doesn’t entail any kind of judgement on the part of the user – ‘there will be a meeting for newbies on Thursday to go over the basics’. However, it is often used in a derogatory context, with older more experienced members looking down on new members and finding them a distraction or an irritation – ‘just ignore the newbies, they’re not worth the trouble’.
In the derogatory context you might find ‘n00b’ to be more common.
Newbie certainly has more history than this – in Vietnam, new arrivals were often referred to as newbies, and ‘non-useful bodies’ was the term given to new sailors on submarines until they had learnt the necessary skills to contribute to the running of the craft (they were often referred to as N.U.B.s, or ‘nubes’) – but it is the modern, technology usage which is most common and most widely-recognised. (Source: BBC Learning English)
(P.S.: Both pictures have been taken from the Internet!)