Not "many", ALL. Each and every ICO review or aggregator site thrives on the money it gets from promoting those ICOs. They are group of people similar to HYIP promoters and they even ask for premium money to be paid to get a project listed on the front page. These PR firms are nothing but scammers who have learnt how to run a scam in the name of a business. Fact is that you cannot brand them as scam since they are only promoting the projects or barely listing them in one place.

Do your own research and if you are in doubt invest in bitcoin only.