I know your question was directed at Lien, but I am pretty sure that it is not the job of memrise to curate all the community courses in this way. Memrise provides the platform and looks after the courses made by the memrise team, as well as all the technical stuff that makes all of this happen.
There are thousands of courses on this site and it would be impossible for the small memrise team to keep an eye on
every single one of them. That is part of the reason - I guess - that this forum was created: so that there can be communication between memrise users who are doing different courses who can pass this information on.
As far as I know, there is no way for a regular user to tell how old a course - beyond looking at the age of the oldest mems on the course. On one of the Swedish courses I do there are a few mems which are six years old, so it is clear from this that this course has been around for at least six years. The only way to find out if a course is actively maintained is to come to the forum and find out if there is an active forum dedicated to improving the course.
That would be my advice for you in future: before you start any new courses, check to see if there is an attached and active forum for it, with someone or more than one person working on making changes to the course.