A syndication service that delivers commentary from 600 bloggers for use by newspaper publishers launched Tuesday, further blurring the lines that divide blogs and mainstream media. BlogBurst, as the service from blog technology company Pluck Corp. is known, includes headlines and articles for use by newspaper publishers in the news or feature sections of their online services, as well as print editions. Pluck initially has signed up Gannett, Washington Post, San Francisco Chronicle, Austin American-Statesman and San Antonio Express. Eventually, the Austin, Texas-based company will offer BlogBurst editorial materials to niche business and overseas publications.