MarkLogic is a fairly unique platform that can provide impressive infrastructural services for XML storage and processing. It's also very good at searching its own repository.
So why don't we review MarkLogic in our Search & Information Access research? It's a fair question to pose, and some of our subscribers do ask, often after talking to MarkLogic salespeople.
To answer it, my colleague Theresa Regli and I wrote an advisory paper "Is MarkLogic an Option for Enterprise Search?" It describes what enterprise search is; what MarkLogic is; and why MarkLogic isn't enterprise search.
Subscribers can download the paper here.