There are many websites that offer this kind of job. If you have that writer in you or you have an opinion on something, you can always share it with them. Even if you are not a very good writer, what other companies are looking for is your opinion about a certain subject. It will be better if you have knowledge of the subject, because in this way you will be able to explain the details of the subject thoroughly.
This line of business is for people who want to earn extra during their spare time. Some do it just because they enjoy writing. Let's face it, due to the fact that the economy is starting to get pretty tight, people start to work hard or try to look for something that would help them earn extra. The advantage of this is huge compare to the disadvantage impact of the writer has to say.
Advantages - Writing reviews are basically telling others your opinion about the subject. For example, as a consumer, what do you think of products that are currently hitting the market? Let's try making sliming drugs or food supplements as an example. Because there are various products and different manufacturers, each of them says that they are better from one another. Consumers will be confused on what to buy specifically for them. And because it is a form of drug, the fear of therapeutic claims or side effects is always there. These reviews will help your fellow consumers with what they need to know and for them to compare these products. The opinion that the writer will be contributing will be a great help to readers because of this info. Writing reviews does not only revolve on one subject, there are many topics for you to share your opinion like politics, computers, movies and many more. The idea is that you will be the primary source of information or one of the references that others will be looking up to.
Disadvantages - You are not the only person who has an idea of the certain topic. There will always be competition and oppositions to your opinion, but you don't have to be discouraged. Remember that you are just giving your own opinion and there is nothing wrong with that. Writing reviews as what has been mentioned do not revolve on one subject. Sometimes, writers post replies to other writers' opinion. It can be something positive or negative on what the writer wrote. At least it will make the subject more interesting and if readers noticed that there are many replies on such thread they will again look up to you. The common disadvantage would be negative feedback from other writers that will sometimes makes you feel down.
Writers contribute their opinion in various ways. Most of them write blogs on websites on what they think and have experienced about a certain subject. There are also writers who post their review in a form of a thread so that reader, if they have questions, could reply to this thread or other writers could comment on the subject as well.
It does not matter if you are not a good writer. What counts is the idea you have contributed about the subject for the readers. With this, you will also be paid by various websites where you have posted your opinion. The more opinion on various subjects means the more pay you will get.