Parsers retrieve syndicated content and parse them directly into the html source of your home page. With your home page content changing frequently, search engines will re-crawl your site more often. And fresh content is indicative of a more authoritative web site. The parsed items will have content related to the terms you want to be found for in searches. Since that content is now part of your home page and it changes frequently, you will be ranked higher for related key phrases. Content is re-cached every 12 hours.