I would urge all users to report bugs when they see them. It really does help us develop a better product.
There are indeed people at Maplesoft who try to monitor the forums and record bugs, but frankly, bugs can get easily missed. Many bugs are exposed in lengthy threads after much discussion about whether certain behaviour is truly buggy or not. Other bugs are mentioned in passing in discussions about unrelated topics. I much prefer to have a bug reported directly by the person who had encountered it than have it reported second-hand.
Apart from those employees who maintain MaplePrimes, there are several Maplesoft developers who participate regularly. However, it is a bad idea to rely on us to record bugs. First, monitoring MaplePrimes is not part of our offiicial duties, though we are definitely encouraged to participate. Our primary duty is to develop and maintain Maple itself. Many of us participate on our own time or we take time away from our development work to do so. Our managers generally trust us to use our time wisely and as we see fit, but alas, there are deadlines to meet and bugs to fix. So developers come and go, and they participate when they have time, which is not always.
There is no obligation to you, as a user, to report a bug, and mentioning the bug on MaplePrimes is certainly better than not reporting it at all, as there is a chance someone will see it and report it for you. However, the only guaranteed way to tell us about a bug is to use the "Submit Software Change Request" link or contact Maplesoft Support.