Day 1: Girl posts stuff online and reads the message, but doesn't respond because it's no longer relevant (I can understand).
Day 2: Send a meme/video to the girl. Girl doesn't read the message but posts something later in the day.
Day 3: Should another message be sent to the girl (to check up on her)? Or should she be left alone because anyway the ball is in her court?
What if it's a girl who usually seems to care about you (and your well-being) and who has been inviting you to hang out a lot of times lately?