No, its of course not! This website is for people above 13, including adults and matured people too as stated in the site page.
Many new folks specially teenagers join this site because of their desire to learn about the mysterious things, the desire often found in youngsters. But there are matured and aged people here as well who are well learned and have knowledge who are involved in witchcraft etc. Moreover there are people under 18 here too, who are matured as well and have knowledge. As it goes, don't judge a book by it's cover.
This site is for one and all.
Those numbers that you see are deleted profiles, I believe. I came across a few myself, and every time, it was a profile that had been deleted. If you look to the right of where the picture would go, you'll see the following:
This account has been deleted
Although, not every profile that has been deleted will be given the new user/number name.