Reviews are like flyers in your local travel agency - some have no impact on you whatsoever, but some make you want to visit a certain place so bad that you literally can't wait to reserve a flight and a hotel. Writing a review is not about convincing anyone to do anything. It's about giving some honest opinions about a given product and listing its pros and cons.
Here's the core of the problem. Too many businesses (online and offline) tend to focus only on getting new customers and forget about taking care of the existing ones. For instance, have you ever seen a TV ad of a mobile network in which they're announcing that everyone who signs up for their services will receive a new iPhone for $10 (or something similar)?
Well OK, maybe not the most, but it's still pretty counterintuitive. I don't intend to keep you hanging, so let me just go ahead and tell you what the advice is: Instead of looking for an untapped niche, enter one that's already crowded. Why? Here's the answer.
So far we've been talking about things like: services and consulting, products, affiliate income, and advertising. These are all valid online business models. Today let's focus on something that is not that obvious, but has been fairly popular lately nevertheless - subscriptions and membership programs.