Social Media sites are useful for more than watching cat videos. The truth is your social contacts can provide insightful information that can help you plan a better vacation or trip. Post a status update requesting tips for a specific location or for a good vacation spot. Engage with respondents about what they liked and what they would do differently. Find hidden gems or that extra special restaurant. These are your contacts so their recommendations should be better aligned with your likes and dislikes.
Security Warning: I have to add a note about being careful about how much info you share on these social networks. It's a great idea to ask for tips, tricks and recommendations but don't post messages about when you will be gone, unless you want your house broken into. Thieves are often looking for status messages indicating travel. Also make sure your posts about travel are only shown to a limited group of people (in Facebook make sure it is only available to friends or a specific user list).