I did a small search before posting this but nothing came out, so here we go, I'm really sorry if I didn't search properly though

One thing I love about Manga Updates is it's categories, they're so specific and that's pretty useful to the point that I have found nice mangas using them. But honestly I think there's just one thing that's missing here, and it's a space for automated recommendations on the index page for logged users, just the way Manga Rock works as manga database (As we all know it doesn't have mangas itself anymore): it recommends manga according to the ones that you actually liked.

Considering the categories here works using votes to show how relevant the category is, for a certain manga, and also considering that Manga Updates keeps a small statistic about genres liked by the user on his/her profile, I think it should be possible to do this and using MU's categories the recommendations would be really accurate due to how specific they're.

Maybe you could keep a statistic for categories liked by the user (or check the categories for mangas liked by the user and take the most voted categories) and then, according to these statistics recommend mangas with the same relevant categories in the index page (only if the user is logged, to avoid no user object exceptions i guess).
Obviously the recommendations should exclude mangas in user's lists.

I actually think that would make the index page pretty useful, and it would make easier to the users to find new manga.
Also, sorry for any grammar mistake, english isn't my first language.

Saludos 😀

Great idea!