No, I'm not asking you to join the Army. But I hope you will do your part to stop the spread of fake news, disinformation, and other misinformation. Here are some ideas:
Don't forward/repost a story without reading it first.
If you use your skills for identifying disinformation or misinformation, you can simply choose not to forward the story, repost, etc.
Share the information you learn about fake news and misinformation and how to spot it with others.
This is obvious: Don't create or spread misinformation and disinformation!
(Not Really)
To learn more about the famous poster above, see information within the American Treasures of the Library on Congress at http://www.loc.gov/exhibits/treasures/tr11c.html#obj23.