The number of internal available fields in the jpeg EXIF standard is amazing. It even supports storing the location (long./latt.). Some digital cameras even support plugging in a gps so it can automatically record the location a picture was taken. While my camera does not support this, I do plan on taking my GPS with me on trip with the intent of explointing google maps. With all the hacks to google maps, one that I expect to see a lot of in the future is the use of Google Maps for travel logs. The ability to show a line on the map of where you have been, and then tabs on the map showing where pictures have been taken (and linking the images) and tabs linking journal entries.
While it is possible to do now, it does not seem to be easy. Over the next year or so I expect we will see tools to do this for you. Probably the hardest feature will be the tool to let you with draw the path for where you have been or let you download the trail from your GPS.
Actually, since most cellphones come with cameras, and some come with GPS built in, I suspect features like this will become available for cell phone users in the near future.
I suspect a lot of people will use features like these for travel, but I think even more will use it for urban exploration and graffiti spotting.
The downside might be an increase in tresspassing citations and arrests. Over the years, as photo logs of urban exploration where people break in to old closed down buildings and facilities in order to get some great pictures has increased, so have the number of people who have then been cited for tresspassing when the land owners found the images online. It's still a rare occurance, but it is still a concern.
Anyway... I, for one, welcome our (hopefully) new picture mapping overlords.
One more odd travel thing to add to my "must do" list. I want to explore Hashima Island.