While facebook is a powerful addition to missions and charities etc, a simple like does not impact the lives of those in need. For that further engagement is needed - volunteering, giving, promoting etc are all ways to actively get involved.
This is something i've wrote about before in regards to Christian missions and how we can 'sometimes' feel we've done our part by hitting 'like' but often our interest dies as we scroll on to the next update.
Something to consider . . .