Why are sites using copyrighed material?

OK, I admit it. Occasionally, I google my name. Primarily, I want to see if articles, poems, or essays I've written show up online. So, imagine my surprise when I see that several of my copyrighted book reviews that I write for a wonderful site called curledup.com are showing up through RSS feeds on two other sites. One site has an email address listed; the other doesn't. I was wondering how they could run my reviews, which are copyrighted material for curledup.com. Naturally, I sent an email to the site which listed an address, and the email was returned as undeliverable several hours later. It just strikes me as odd how they can do that, and it doesn't seem they should be able to use it without the permission! Yup, this is my vent for the day. :)