"The idea that the date of your birth has any effect on your personality is absurd on its face. But for the sake of open mindedness, let's say that it's possible. Is there any scientific or statistical data supporting this?"
Yes the Gauquelin data and work done by John Addey and others.It's only been around for 50 years or so.
"How would one even measure something as subjective and fluid as human personality? "
Psychologists do it all the time.
"The idea of astrology makes no sense, and with a little digging, it still doesn't make sense. As for who invented it and why, I suspect it was invented by scammers who realized that with very little effort, they could profit off the gullible. "
Typical skeptic first admits his ignorance of a subject, then tells us all about it. Do you listen to yourself? You can learn 100x more than you know right now with five minutes of desktop research, not that it will improve your thinking skills.FYI virtually every culture has developed some form of astrology throughout history. But what is more remarkable is that they all have common ground despite having no contact with each other. For example, Venus is always some form of the goddess of love. Mars is always some form of war or warlike activity. If it was all random, some cultures would use Venus the way others use Saturn, etc. But don't let facts ever get in the way of your prejudice.
"I've seen several questions/answers here about what gem stones people needed to buy to fix their problems. How convenient."
Hmmmmmmmm brilliant Lawyers and doctors advertise and take money for their services, so I guess that makes them frauds, Deep.