こっそりみんな使ってる匿名掲示板 - きいろチャット is a chat and calling platform that allows users to communicate anonymously. It provides a space for users to find friends with similar interests and have fun.

The program offers several features to enhance the user experience. Firstly, there is a bulletin board function where users can post about their favorite topics in different categories. Secondly, there is a direct messaging (DM) feature that allows users to have one-on-one conversations with someone they are interested in. Lastly, the program includes a calling feature, enabling users to have one-on-one voice and even video calls with their DM contacts.

The bulletin board categories include "All", where posts from all categories are displayed, "Personal Thoughts" for sharing personal thoughts and conversations with specific individuals through replies, "Chat" for chatting with people on the timeline, "Q&A" for conducting surveys and asking questions about the app, "Otaku Room" for freely posting about gaming, hobbies, and interests, "Recruitment" for various recruitment purposes such as finding gaming buddies, and "Self-Introduction" as a place for users to introduce themselves when they join the app.