Writing down where every signup came from is much easier if each place you post gets its own UTM link before launch day, so you aren't piecing it together from memory afterwards. Some directories and apps strip query strings, so an optional "Where did you hear about us?" field on the signup form catches what the links miss. For answering every comment, it helps to prepare a few things ahead: a two line description, a screenshot of the result the product gives you, and a short clip of the main task. A lot of first comments are some version of "what does it actually do?", and a short clip answers that faster than a paragraph.