For blogs and online forums that excerpt content from other sites and post third-party content (like content), in order to enjoy “safe harbor” status under the DMCA, the site must register a contact for takedown notices. Costs $105 (plus postage) but can end up saving a bundle down the line. See this Wired article, which talks about a company called Righthaven which is buying up the rights to old newspaper material with the sole purpose of suing those who posted quotes from it online, and is targeting sites that do not have a registered DMCA Takedown contact:
Under the Digital Millennium Copyright Act, a website enjoys effective immunity from civil copyright liability for user content, provided they, promptly remove infringing material at the request of a rightsholder. That’s how sites like YouTube are able to exist, and why Wired.com allows users to post comments to our stories without fear that a single user’s cut-and-paste will cost us $150,000 in court.
But to dock in that legal safe harbor, a site has to, among other things, register an official contact point for DMCA takedown notices, a process that involves filling out a form and mailing a check to the government. An examination of Righthaven’s lawsuits targeting user content suggests it’s specifically going after sites that failed to fill out that paperwork.
“The DMCA is a good deterrent from being sued,” says Kurt Opsahl, a staff attorney with the Electronic Frontier Foundation, “Complying with conditions of eligibility for the safe harbor is a good thing to do. It probably will prevent somebody from suing you in the first place.”
(Hopefully that excerpt is short enough to be considered fair use, combined with the citation and link. Would be kind of ironic if I exposed myself to a legal troubles by quoting from an article that talks about how you can avoid such things). An alternative is to use a hosted service for your blogging, who will have already registered a takedown contact and will handle all DMCA notices.