[RichardPrice]

It's worth noting that advanced search is a relatively new feature, developed for the premium account. The majority of discovery on Academia happens via social mechanisms on the site: seeing what people you follow are uploading/sharing/commenting on/recommending.

Even though advanced search was requested quite a bit by our users during our research around what features to build for our premium account, other premium features have been more heavily used than advanced search. The social mechanisms have remained the primary way that people discover research on Academia.

[JulienSchmidt]

I really appreciate your efforts. One of the most frustrating things to encounter as a student doing research is a pay-wall.

Regardless if such kind of search was available before or not, many people, like the author of the linked article, will encounter this pay-wall during their research. I think you could benefit, and especially grow, a lot if academia.edu becomes a place where students actually start their research instead of landing there through an external search engine.

In 2017 fulltext search should be considered a basic feature, which according to your business model should be free. Even the online library of my university offers it, even though on a much smaller data set.

If it is true that other premium features are more heavily used than "advanced" search, then you still have enough reasons to legitimate your premium accounts without it.

I think you could find other ways to generate income and become sustainable. For academia.edu it might be premium accounts offering additional services and maybe sponsored content like placed search results, job offers etc. Use the information you generate (but please don't just sell it to a 3rd party).