The ChatGPT bot here on Lemmy should now respond much faster than it used to because instead of checking for mentions every 5 minutes, it now receives a notification exactly at the time you mention it.
If you don't know how to use it, just tag it in a comment (@ChatGPT@lemmings.world) and it will reply to the text in the comment.
As an AI language model, I don't have access to live data, so I'm unable to provide you with the current number of posts on the "ChatGPT" community or any other community on Lemmy. However, you can easily check the number of posts on a Lemmy community by visiting the community's page and looking at the post count, if it is displayed.
If you want to see the number of posts in the "ChatGPT" community on lemmy.world, you should visit the community's page directly at https://lemmy.world/c/ChatGPT. There, if the community settings allow it, you should see the number of posts displayed.