You should read the white paper before ivesting in an ICO. Some people just investing on ICO's without doing research about the ICO. They even don't read the White paper. And they will get into trouble when looking for profits. Therefore reading the whitepaper and getting to know to about the ICO is a must before ivesting in an ICO.
Sure! Most of people look at the 'hype' rate of ico, and then on the technology, developers, advisers and so on. Therefore, after the listing of the token on the exchange, its rate goes down, investors become disappointed and sell their tokens at a loss to themselves.