Goodreads is basically the only major social network for bookworms, yet the majority of its users hate it (including me), but are forced to use it to their chagrin.
You would think that would make the market ripe for a disruptor to arrive and topple the incumbent leader, yet each year nothing happens.
I personally have also thought of making a new rival product, but when you do the math on the market potential and the financial benefits, I just don't see a viable way.
People who read books, even if they read them every day, won't use your social network each day since books by themselves are the type of content which is consumed the longest (compared to a movie, tv show, song, or video game).
So you have a social network where users come back on a whim, even if you read like a maniac and try to read one book per week (I tried it one year, it was crazy, you are basically spending all your free time reading), even then users wouldn't use your app each day, but perhaps once or twice a week, and who knows how much time would the average session last?
To make things worse, you could maybe even get away with users using your app once a week if you have a big enough market (user base), but the number of book readers is not that great (especially compared to other media consumption)... The median American reads 4 books a year [1], or simply put, one book in three months.
So you have a social network where users don't need to use it often and there aren't a lot of users, that already spells trouble, but there is another major issue.
You could even succeed with those issues if you had a highly commoditized product to advertise, let's say a social network for yacht lovers, even if you have a small number of users and they do not use it much, you can still manage to succeed with it, since if you advertise yachts to potential yacht owners, you have a very valuable marketing channel which is worth quite an amount to the right people.
You can see where I am going with this, just compare a 5% commission on a yacht, vs a 5% commission on a book... Unfortunately books are not so highly valued (in monetary terms) nor sought after.
To sum up, you have a social network where users don't spend a lot of time, you don't have a lot of users and it is centered around a low profit product... Of course Goodreads has no competition, no sane person would touch that market with a ten foot pole.
Yet, to quote George Bernard Shaw, "all progress depends on the unreasonable man". If someone manages to solve this problem and find a profitable way to survive, I would not be surprised to see Goodreads fall.
I even thought of contacting Scribd to work with them, since I think they might have the best shot currently to position themselves as market leaders. They have an excellent product (Netflix for books) and already have a well sized user base. Would be interesting to see them expand and also became a social network for book lovers.
[1] - https://www.bustle.com/p/how-many-books-did-the-average-amer...
[2] - https://www.goodreads.com/quotes/536961-the-reasonable-man-a...