Canvas LMS is the core service that universities rely on. I assume they're trying to develop a fix and that's why the service is labeled "Under Maintenance". I'm a Berkeley student and can confirm that our instance (bcourses.berkeley.edu) is still down.
"The basic algorithm divides points by a power of the time since a story was submitted. Comments in threads are ranked the same way.
Other factors affecting rank include user flags, anti-abuse software, software which demotes overheated discussions, account or site weighting, and moderator action."