Ancient Effigies are, in short, elite D&Ds, with a major flaw:
You don't need to get one to get the rewards.
Runecrafting[]
Effigies have replaced the meaning of this skill.
Lost?[]
Yes, much like that annoying television show, this may get just a little confusing.
Jagex decided that when they released the Ancient Effigies, you would need to be level 97 plus in all skills if you wanted to gain the benefits for yourself. If you weren't, you could just seek assistance from an elite player, who would then get the experience.
Which sort of defeats the purpose.
Anyway...[]
While it is incredibly rare for one player to get a sufficient number of Ancient Effigies to automatically get a 99, if one player sets up a clan(possibly of bots), the number of Effigies they receive dramatically increases, and they get tons of experience for nothing.(if by nothing you mean staring at the effigie and somehow "using a skill",then this article describes how stupid jagex is.)