By Women For Women.
This term can be applied to a work, a genre, a business, etc. It means that it's produced by females and targeted at a female audience.
1. Yaoi is overwhelmingly created and consumed by females; gay/bi males are a relatively small group.
2. Some insurance companies specifically target women, but this would only be a true example of BWFW if the company's employees (and management in particular) were themselves mostly women.
Main Love Interest.
The (usually primary) character in a work of fiction who is meant to be the true love of the protagonist. This especially applies to genres where there are many possible pairings, the purest example being harem anime/manga.
In the series Love Hina, Naru Narusegawa is the MLI of Keitaro Urashima.