I understand honour societies have been around for years and it is a tradition more prevalent in the western world to recognise outstanding academic talent.
The largest honour society is perhaps the Golden Key which operates worldwide and has over 2 million members. It provides a range of services to members, including leadership training, networking and the opportunity to do good. Membership is by invitation only and only those who are in the top 15% of their class or high performing graduate students are eligible. The eligibility is based solely on academic performance.
I presume being invited to join a honour society is an 'honour' in itself, as the mere mention of this affiliation on the CV would indicate that you are a top achiever.
Question 1: Does membership of honour society carry any professional weight?
(i.e. does it give any additional advantages?)
Note: Honour society is not the same as professional society. The latter, as I understand it, is open to all persons in a particular field (irrespective of their academic achievement but as long as certain criteria are met, e.g. successful registration as a teacher to join a teacher's union).
Question 2: Are there other honour societies in addition to the Golden Key (which seems to be the most dominant one)?
PS: I am unsure of the tag, so putting CV. Please update!
Disclaimer: I am not associated with Golden Key.