Like other popular names, the advantage of the name Nicholas is that it gives the parents (and later, the bearer of the name) the opportunity to choose between the full name, Nicholas, and a short, single-syllable nickname--in this case, Nick.
Still, the name is decreasing in popularity. Only ten years ago, the name was the sixth most popular name for boys in the US, and its popularity has decreased since then. It could be just a passing decline, or the decline could continue. At least until Nicholas Cage stars in a blockbuster...
2010 Update:
Well, Nicholas Cage has been in some successful movies, but no real starring blockbuster roles. So, the name is now continuing the decline to number 38.
