More simply, the new ICO protocol would give buyers the option to withdraw investment bids on tokens, while evaluating the buyer's stake relative to the entire ICO and shifting bids accordingly. In this way, it seeks to solve the problem of ICO sales selling out too quickly, or not at all. While very much in early stages, it notably follows a flood of ICOs in the past few months that have alarmed industry participants while stoking equal optimism the use case could one day democratize venture funding.

https://www.coindesk.com/ethereum-founder-vitalik-buterin-co-authors-plan-iterative-ico-protocol/