The biggest US airlines involuntarily bumped 40,629 in 2016. According to the Department of Transportation, you are entitled to certain things if you are involuntarily bumped off a flight. You are entitled to a document that tells you your rights, the procedure the airline goes through to determine who is bumped.
If the rescheduled flights gets you to your destination within an hour of your previous arrival time you are not entitled to any monetary compensation. Monetary compensation comes into play if the flight is not rescheduled within an hour. Depending on if you're flying domestically or internationally, the window of time varies for how much money you are entitled to. But airlines can owe you up to $1,350 for a one-way ticket, and you can negotiate for more if you feel entitled.
But make sure you show up on time and have a confirmed reservation, otherwise, you may be entitled to nothing.
Here's what airlines legally owe you if you're bumped off a flight posted first on http://lawpallp.tumblr.com