The Northwest Multiple Listing Service plans to introduce new guidelines later this week which will allow homeowners to decide whether to allow blog posts and automated home valuations (like those from Zillow.com) next to online real estate listings, reports Kirsten Grind from the Puget Sound Business Journal. Grind notes that if an agent breaks the rules — and writes a nasty comment or offers an unflattering opinion of a home — they could be fined thousands of dollars.