Especially for niche products, product visibility is greatly enhanced by technical content written by an outsider. A third-party book authored by a high-profile industry expert makes the product more credible. You could directly subsidize a book, especially if your market is currently too small to make a book financially viable for the author. If you don’t want to get involved directly in a third-party project, many of the techniques described in the section on user community and loyalty can help nurture potential authors.
It is possible or even likely that an outsider will criticize your product. The best response is to engage in a discussion, rather than attempting to stifle their point of view. For example, tell an industry leader that a missing feature is under development for the next version, and ask him or her for feedback on how to implement it. Remember that the outsiders often have more credibility precisely because they are outsiders and not employed by the product developer.