There is a difference between and IPO, and ICO. That being if an investor participates in an IPO you own part of the company as a stock. On the other side of the spectrum, if an investor takes part in an ICO, you own a digital asset coin, that is issued by the company. Usually, the currency is some sort of utility token with its own specific role in the company's ecosystem trading between i.e a consumer, a content-maker and an advertiser.
The increasing demand rises the intrinsic value of the currency sometimes by tousands of percentage. To put this into perspective, the highest performing stock in the S&P 500 rose only 132% in 2017. Whist the top 20 best performing ICO’s rose by an incredible 20,000%. These kind of gains are never guaranteed and can come with a lot of price volatility.
Read the details in the article of Coinidol dot com, the world blockchain news outlet:
https://coinidol.com/guide-to-investing-in-initial-coin-offerings/