Since I don't think that anyone can Mute or Hide themselves, I would suspect that you are viewing the forums with too restrictive a filter on. If your filtered view doesn't have a match to a tag that you've used to ID your topics, then you won't see your topics. You can also try the adventurous and addictive "firehose" of seeing all topics, all tags, all everything, by clicking on the appropriately and conveniently named "All Topics" link in both the upper left listing and in the "Bungie" pulldown under Forums-All Topics.