To add to Marney's answer, a lot of the time you will see several houses go up for sale in a certain area at once because one home owner will see success in the sale of a neighbor's home and decide that they'll give it a shot too because they've been considering selling and this gives them an extra push. Although sometimes it is just pure coincidence.
If you're concerned about there being issues, you may want to check crime statistics in the area which you can do right on Trulia under the crime tab when you're on a specific property page.
Another recommendation, if you're really interested in an area, is to drive through the neighborhood during the day, evening and on a weekend to see it at different times of the day/week. If you have any other questions or would like to go take a look at some of these homes in person, please don't hesitate to contact me any time. :)
Marika Clark, Realtor
Keller Williams Select Realtors
696 Ritchie Highway, Suite 100, Severna Park, MD 21146
c. (443) 572-9169 | o. (443) 261-1100 | e. email@example.com
"Nothing worth having was ever achieved without effort." - Theodore Roosevelt