Wikipedia
Photowalking is a communal activity of camera enthusiasts who gather in a group to walk around with a camera for the main purpose of taking pictures of things that interests each photographer. Although the term implies the single activity of taking pictures while walking, the more modern use of the term specifically relates to a communal activity of camera enthusiasts.
The activity is typically organized by camera clubs, ad-hock gatherings from online forums such as Facebook or Twitter, or sponsored by commercial organizations. These events usually take the form form of a designated walking tour with a planned route or map. Often the aim is to practice and improve one's own photography skills rather than a specific focus on documentary photography.
While the camera need not be a digital camera or a DSLR, in practice the low cost of digital photography and the ease of digital photo processing and online photo sharing allow a casual approach in photowalking.
As with any walking that may go a few miles or kilometers, photowalking can also promote physical fitness.