I've noticed that most people when posting a pic of their car blank out the number plates, why? what's the reasoning behind it?

Maybe to protect their privacy. You could possibly get owner's details through the number plate? I'm not sure

Also, if they decide to sell the car later on and the number plate is visible on both their ad and on some thread in a forum, people can easily find the car's history by searching through all the poster's threads too.

Yeah, I've wondered why people do it too.... the weirdest thing is in For Sale ad's ppl blank out the number plate in the photo's, and then by law in most states have to quote the rego of the car anyway !!!

http://forums.aussieveedubbers.com/viewtopic.php?tid=84629 
For an example

It's not hard to find someone's address from a numberplate if you know a bent copper...

Another reason is you can do a "REVS" or Vehicle Securities Register search on the car and get the VIN and Engine number. Then use those details to rebirth a stolen car.

People often do it if they're tracking their car and aren't covered by insurance for track time. I guess it by some small chance an insurance agent recognizes the car they could void the entire insurance.

I've seen on other forums when someone has posted pics of something they have done to their car, another person with a grudge has dobbed them in to police with a rego number

It's a good idea to cover your number plates on track days, as it possible - and probable - that insurance companies could get hold of that info. They could keep it on record, and deny your claim, saying that have been 'racing', and are not covered! In the meantime they will keep accepting the premiums.

Quote:

Originally posted by Sides Yeah, I've wondered why people do it too.... the weirdest thing is in For Sale ad's ppl blank out the number plate in the photo's, and then by law in most states have to quote the rego of the car anyway !!!