In the greater scheme of things, 500 posts is really no big deal.
Honestly, there are people marking much bigger things than blog posts.
Here are some that pop into my mind.
Can you think of some more?
500 days cancer free
500 days to write a good book
500 calories not eaten
500 miles ridden on a bike
$500 dollars raised for charity
$500 dollars bonus in your paycheck
$500 dollars for a round-trip ticket to Australia
500 days of 3 meals a day
500 days in your new home
500 days married
500 minutes until your soldier comes home
500 seconds since your first child was born
500 pennies when you're five years old
500 quarters when you're homeless
Add to my list.