Creeping on other people's posts

I noticed that when I’m looking through someone's post history, it only displays 15 pages.
Does this mean there's no way to dig up anything older than that? Like, if I'm specifically trying to track down everything a certain user has ever posted, am I just hitting a dead end once I pass those first few pages?

You can basically search by entering a username and selecting a specific subforum, or you could just filter by a date range or some keywords.