As you may have heard before "content is king". Bloggers are mostly content writers. It is the content that drives traffic to your blog or website. To get more web traffic, you would add more useful content to your blog/site, however you might not be able to come up with quality content as regularly as you might wish(Reasons could be laziness, lack of motivation/interest, blogging fatigue, monotony etc.). In this situation you probably would want to keep your blog fresh with new content by getting free content for your blog/website.
The easy-lazy way is to use the free available content from article submission directories, which host articles from variety of authors on various topics, most of the directories will let you use the content if you follow the terms of usage and give proper credit to the author. Most times, you just have to publish and unlatered with the author/site credit resourcebox in the post footer. However do read the republishing terms of the sites, whose content you want to use as the terms might be different for different sites.
Here's a big list of article directories ( Bookmark & Share!) :
http://www.articledashboard.com/
http://ezinearticles.com/
http://www.content-articles.com
http://www.justarticles.net
http://www.amazines.com/
http://www.free-articles-zone.com
http://www.myownezine.com
http://www.articlecity.com
http://www.websition.com/
http://www.isnare.com/
http://www.articlesbase.com/
http://www.theleadingarticles.com/
http://www.articleworld.net
http://www.bestmanagementarticles.com
http://www.ladypens.com/
http://www.articlesandauthors.com/
http://www.articlerich.com/
http://www.article99.com/
http://www.ezau.com
http://www.articleblast.com/
http://www.articlesfactory.com/
http://www.seo-writer.com/reprint/articles.html
http://www.my-articles.com/
http://www.en.articlesgratuits.com
http://www.activeauthors.com/
http://www.articlestreet.com/