You really want to sell your home. Like yesterday. How are you shopping for EVERYTHING now days? On the interwebs, of course. Seriously, HOW does Amazon know what I want to buy before I even know I need it?! But be careful when signing the listing agreement with your agent. In the listing agreement (for DC, on page 3) there is a category called "Marketing/Virtual Office Websites," and you're all like, "Huh? Yeah, I want it online. Duh." Oh, but read closer (cue scary music):
Question 2 asks if you authorize your listing address to be displayed online. For most, this is not a problem. However, for many people in this area, depending on what type of job you have (CIA, FBI, DOD, DOJ, etc.), you may need to be careful about selecting that option.
More importantly, question 3 says you authorize the display of an "automated estimate" of value to be displayed. Understand, when we as agents put a listing into the MLS, sites such as Zillow, Trulia, etc., pick it up, often through no prompting by the listing agent. Do you really want some mindless auto machine without decision-making capabilities assigning a value to your home based on the piece of crap tear-down that sold next door a year ago? Your home has class! Your home has stainless steel! Your home has parking! Your home has paint from Crate and Barrell! No. You don't want Zillow's autotron telling everyone and their grandma what your house is worth. Especially when the good people at Zillow don't even BOTHER to come over and see your castle. Check "no."
Lastly, question four asks if you authorize the display of unedited comments or reviews of the property on MLS participants' websites. This means that agents can blog about your listing (fine), and others can post comments to that blog. So, OK, you had a FEW too many last Halloween and decided to TP the house of that lady down the street with the dog that barks all night. Well, she's been lying in wait and biding her time to avenge her trees, and now she finds your house on a blog and comments that it's haunted and there were 12 murders there last year and YOU might be the culprit (dude, it was a Halloween party, and that was my weird Uncle Bob, not a ghost, he's just really old). Anyway, be careful about allowing the general public to comment on your house any and every where they feel the urge.
Bottom line, you want your house to have as much exposure as possible, but make sure it's accurate, safe, and in good taste.