No-one owns a hashtag. So the good news is that just because somebody might use #MayThe4th for one purpose, it does not prevent you using it for another purpose. Here are some great options for using #MayThe4th. You can feel free to copy-paste any of the items in the text-bubbles into any social media you like.
Seasonal
Use the hashtag as a seasonal expression. The date of May the 4th is typically a spring day in the Northern Hemisphere or an autumn day in the Southern Hemisphere.
So you can put something like this:
#MayThe4th is a wonderful spring day here
Enjoying the autumn leaves here on #MayThe4th
The significance of the number 4
The 4th occurrence of something may not be as exciting as the first occasion, but it has its own significance. Try any of these:
#MayThe4th time you do a new good habit is when you stick with it
#MayThe4th please come after the 3rd and before the 5th item, otherwise something is clearly wrong.
#MayThe4th wall be broken in awesome ways
May the 4th in history
Many interesting and exciting events happened on the 4th of May in an earlier year. Let's take a look at some of these (information obtained from reference 1):
The first Grammy Awards were on #MayThe4th 1959: Perry Como and Ella Fitzgerald win
On #MayThe4th 1924, the III Summer Olympic Games open in Paris
#MayThe4th 1899 was the 25th Kentucky Derby, the winner was Manuel
The Cincinnati Reds played their first baseball game on #MayThe4th 1869
Cited sources:
1. What Happened on May 4 from On This Day