Software is something you buy and renew maybe in 5 years. I want to learn what types of techniques did getapp or g2crowd use in order to retain customers? Can online consulting be a good solution for this?
It's the product itself, the idea and accuracy of customer reviews, specifically whether there's a match for end client.
Consulting on top of it can be used as one of additional nice-2-have features, but not primary focus. To make a parallel, some time ago there were info call centers, most of them used Internet as a source of information and charged customers for using their phone line (sort of wrapper, mediator between source and customer). So once customers started using Internet and bought smartphones, these info services became no longer required.