Advertising one's publication
Eykanal is basically right, but there's a fine line between networking and being annoying.  There are plenty of circumstances where sending email to more famous/senior colleagues is perfectly fine.

If you already have a professional relationship with someone, it's perfectly fine to write a quick email saying something like "Thanks for the great lunch conversation we had at [conference] last month.  You might be interested in this paper I just wrote."  Yes, a recent lunch conversation counts as a professional relationship.

If you don't already have a professional relationship, then you should probably limit emails to a few key people who have a direct connection to your paper -- either you build on one of their results (which your paper cites), or improve one of their results (which your paper cites), or they've written papers on closely related topics (which your paper cites) .  But within those constraints, emailing your paper is perfectly fine; everyone likes to hear that their work is useful and interesting.

If you do send your paper out, be sure to welcome comments, but don't expect a response from anyone.  That silence from Famous Person On The Internet doesn't necessarily mean that they aren't reading your paper; they're probably just really busy.