There must be a catch with these properties, what is it?

[Jared G.]

As I browse Zillow for properties in Baltimore, MD, I see many houses with multiple bedrooms, selling for under $150,000 with mortgages of less than $700 a month. I am familiar with the areas and know that they're not bad at all, and the photos show clean, nicely renovated places (new appliances, granite countertops, etc. - the typical good-looking family home). Yet, many of them say they've been listed for more than 100 days.

Why? Are there certain things wrong with these places that don't appear at first glance? Why wouldn't they have been bought? What's the catch, or what are possible catches in this situation? What other numbers and data should I be looking at?