Facebook wants to know “what’s on your mind?”  Twitter asks “what’s happening?” But that’s getting old already.  The burning question for the next wave of social networking is “where are you?”  Services like Foursquare, Gowalla, Brightkite, and Loopt want you to use your smartphone to answer.

The technology at the heart of this trend is called geolocation; and with a GPS-enabled smartphone such as the Apple iPhone, Google Nexus One, or RIM BlackBerry, you can use it to let your friends know where you are, or to find places recommended by people you know, or to check in remotely at clubs, bars, and restaurants.

Flickr introduced its own new geo-local feature called Geofences, a security feature intended to keep creepers away from your most sensitive location information.  Adding location information on Flickr is done through the Organizr, under the Organize tab. In addition to the “Your Sets” and “Your Groups” tabs in that area, they will add a Maps tab where you can drag photos into a Yahoo Map area.  A marker will appear that shows the number of photos included with that marker. Once you have a location, you can use the Organizr to search your photos and drag them individually or by sets into the map.

Geotagging the location of your photographs can add context to images, but it can also expose your location to anyone viewing your photos. A geofence is a special location that allows you to set up restrictions on who can see location information based on where the photograph was taken.  With the new feature you can draw a circle on a map to designate a geofence and then choose a geographic privacy setting for the area.

But Flickr isn’t the only network adding more photo-driven location features.  Twitter added its new feature of uploading photos over the summer, with the option to attach them to tweets from the Twitter site, a feature powered by Photobucket.

Photobucket CEO Tom Munro predicted that mobile photo tweets will scale rapidly in coming months. With its photo uploading features twitter.com, released some survey results this week looking at mobile photo and video uploading trends.

“With Twitter releasing their developer APIs, likely extending photo sharing into their mobile platforms, and Apple’s announcement of deep Twitter integration to all of its iOS-based devices, we believe mobile photo tweets will scale rapidly in the coming months,” says Munro.

“The improved quality of photos and videos from camera phones, ease of uploading and constant availability are making them the default device for image capturing and sharing.”