I'll break from the crowd and tell you not to do it. First because I wouldn't personally find it useful. Second because this space is very crowded with people v

I'll break from the crowd and tell you not to do it. First because I wouldn't personally find it useful. Second because this space is very crowded with people vying for affiliate revenue and you will have a long and slow crawl to any organic visibility, and third because the lack of progress/activity among the sites that you list suggests there is very little in the way of revenue anyway. Do something you really care about and that solves a problem for someone. Finding sequels to books is not a problem I think anyone has.