Well, it's the next logical step...
You know, like when you first start, you finally get 50 posts and you can give rep and other things. A bonafide member of the community.
Soon enough, you hit 100 and you feel proud. You also found out that your lame posts in the cave didn't count.
Then the next major milestone is 1000 posts. Oooo, now we're talking. Been around for awhile, learned a lot, helped some others along the way. when you give advice, people look at your post count and marvel.
The rest of the thousands are not so significant, just trivial mindless banter in the forums until.... you hit 5000. That's a major breakthrough. That's a lot of talk. That's a lot of posts. That's a lot of spewing of BS.
And you get to thinking, wow, If I made it this far.... I wonder what it will be like at post #7148.... But henry, you're way past that mark, you probably don't remember....