Hobo's were generally Men who were down and out after the period of the early 1900's. Most of them had Trade skills and a bit of a work ethic. They traveled to get worked. Tramps traveled but didn't work, and Bums & Vagrants didn't travel or work.
Most of the Hobo's did to some degree mooch rides on freight trains, or hitch hike to get from one source of work to another. But in those times in the USA it wasn't as industrialized so the work supply was sporadic. The "seniority system" wasn't in place so much either, so Men tended to drift after earning some money to travel and see the country. Boarding Houses were a common cottage industry and there wasn't Government breathing down everyone's necks to inhibit or regulate any industry they may have had.
(such as running a boarding house where working Men could get lodging and meals)
The YMCA's are probably the best last vestige of boarding homes today. They're known for their tiny rooms
and cafeterias with excellent food. Beyond that they are affordable.
Mark Twain once commented on this stating that modern Men didn't have the opportunities he had had to travel and work at different things and get "a new perspective" occasionally. Industry and the seniority system gave young Men in the 20th century an initiative to stay in one place and to settle with a family.
Other Authors such as Steinbeck told a story of being out on the road in "Of Mice and Men". It was a difficult life and after reading it you can begin to see how Hobo's relied on their symbols they would use to share valuable information with others who were traveling as they were.
There is more information and symbols in this website:
http://www.worldpath.net/~minstrel/hobosign.htm
http://www.worldpath.net/~minstrel/hobosign.htmNational Hobo Gathering Britt, Iowa Aug 3-9 2015
http://www.brittiowa.com/hobo/
Perhaps some of the Van Travelers and RV full timers should visit this if they are nearby and take in
the gathering and let them in on how people today are once again for work and leisure.
BuzzFeed report on attending the National Hobo Convention
http://www.buzzfeed.com/mjs538/things-i-learned-at-the-national-hobo-convention.