Choosing a subject for a review site

A review site earns when somebody reads it, decides, and buys. That sentence contains the whole of niche selection: you need people who are about to spend money, enough products for them to be deciding between, and a reason to read your page rather than the retailer's.

The conditions, and why each one is there

• People buy in it. Not interest, purchase. A subject with a large curious audience and no transaction produces traffic and no income.
• There are many products to compare. More products means more articles, and comparison is the format that earns.
• The items cost enough. A commission is a percentage, so the same work on a 300 item returns many times what it returns on a 10 one. This is the condition most often ignored and it sets the ceiling on everything.
• Buyers research first. Nobody reads a review before buying batteries. They read several before buying a mattress. The deciding question is whether being wrong is expensive or annoying.
• You can tell the products apart. If you cannot say which one suits whom, your page is a list, and a list is what the retailer already has.

Those five are not a scoring system. The third and fourth are close to mandatory, and a subject failing either is usually not worth the year it will take.

The arithmetic, before the list of ideas

Illustrative, and worth doing before committing a year. A category where the typical purchase is 200 and the commission is 4% earns 8 per sale. If one visitor in fifty who reads a comparison goes on to buy through your link, that is 0.16 per visitor, so a page attracting 500 visitors a month earns perhaps 80.

Now the same arithmetic in a category where the typical purchase is 25. The same traffic, the same conversion, and about 10 a month. The work per article is identical. That gap is the entire argument for choosing on price, and it is why enthusiasm for a cheap category is an expensive preference.

Where the conditions tend to hold

Not a ranked list, and not advice to pick one of these. They are examples of what satisfying the conditions looks like, so you can recognise it in a subject you actually know.

• Household appliances and kitchen equipment. Constant demand, endless models, prices high enough to matter, and buyers who research because returning one is a nuisance.
• Outdoor and sports equipment. Expensive, and quality has consequences, which produces careful buyers.
• Home working equipment. Chairs, desks, monitors. High prices, long use, and comfort is hard to assess from a product page.
• Pet equipment. Repeat purchase, and owners who read recommendations from other owners.
• Equipment for children. Heavy research because safety is involved, which is also why accuracy here is not optional and a careless page is a genuine harm.
• Software and online tools. Often recurring commission, which compounds unlike a one-off, and it requires actually using the tools rather than reading their marketing.

Two warnings attached to that list. Each of these is competitive precisely because the conditions hold, so the realistic entry is a narrower corner of one rather than the category itself. And several are seasonal, which affects cash flow rather than viability, but should be known in advance rather than discovered in February.

The thing the retailer cannot do

This is the question that decides whether the site is worth building. The manufacturer has specifications and the retailer has stock. Neither will tell a reader which option is wrong for them, what the thing is like after six months, or which cheaper model is good enough. That is the entire product of a review site, and a page without it is a worse version of the retailer's listing.

Which is also why having used the things matters commercially rather than only ethically. It is the only part of the page that cannot be produced by somebody who has not, and therefore the only part with any scarcity in it.