Hello Caro.
Ranking is based on number of posts. Administration also awards symbols on an individual basis to members who have demonstrated positive qualities in the course of their participation here:
Checkmark = Proficient Speaker
Gavel = Administrator
'Yin-Yang' Taoist symbol = Moderator
Picture of Two People staring at a Checkmark = Professional English Teacher
Angel - Trusted User
These are placed under the avatar to the left of each post. These do not mean that other members, junior or otherwise, are not excellent advisors. The site administration can only do with and monitor so many valued assistants. In the end, this is the internet, and you can only see what you read on your screen: you must consider the advice given and decide for yourself whether it is of value to you.