Elizabeth Coe sent 100 friends a link to her company's website. This feat got her booted from Facebook — and got her featured in the opening of a Washington Post story about Facebook's spam-fighting effort. Facebook is now banning users who ask too many people to be friends all at once, send too many messages, join too many groups, or "poke" too many people. "All I was doing is using it to communicate more efficiently, which is what I thought it was for," Coe told the Post , which goes on to explore the ins and outs of Facebook's unpublished rules.This much is easy to understand: Sending 100 friends a link to your company's site is spam by any reasonable person's definition, whether you think it's "efficient" or not. Facebook has to crack down on such behavior because its users are getting sick of a surfeit of irrelevant messages, whether they're from friends or advertisers. Web security firm Cloudmark says 37 percent of Facebook users have noticed an uptick in spam over the past six months. What's more, Facebook is dealing with an increasing barrage of worms, viruses, phishing scams , as well as security threats for which researchers haven't invented suitably scary jargon yet.