This is actually a pretty fun way of making some money. Although it is not a guaranteed income, but I find it fun to know what are people actually trying to start and at the same time, suggest to them a domain. If it is picked, you will be paid USD25 via paypal, simple.
I thought of a trick that might be fast and useful if you are interested to make some money from this new service. You will need to make a list of prefix and suffix. For example, you can use mydomain.com or domain4all.com. Make a long list and try to include them in your suggestion.
If you are looking for a good domain, it will be a great source to spend USD50 as you could potentially and easily earn back your USD50. Your domain is always there to stay, therefore it is advisable to invest in advance.
