The Women's March in January was successful because it had a clear, credible target: The Trump administration and its policies (defunding Planned Parenthood, etc.). Judging from how my Wednesday is going so far, the call for a Women's Strike is looking like it's going to be a poorly attended event. The earnings gap is a complex matter and its cause, in the Western world at least, is rarely discrimination, if at all. Family and career choices are the major causes in my view and and it's not as easy to figure out how to protest that. For a march to be successful, I think you need to target clear and concrete issues (the need for affordable daycare for example).