we don't need to think that all ICOs are scams... There are many really good teams now who are trying to launch a new coin but they are also trying to make a wide and strong community and have some really demanding technologies behind this.
Not all icos are scam but a good number are, they make promises about a project and people give to them millions of dollars and then after some time they just disappear with all the money they got from their investors and after sometime they come back to the forum to try to scam members once again.
they dont need disappear. they just say project fail and sorry, very sorry. that's all. so check team profile is very important.
yeah because there are so many cases like that, so doing picky and research before choosing ICO is the most important thing, maybe first you can see the formation and profile of dev team, then the seriousness of the project they are working on, then their innovation, if all is clear , you can start choosing that ICO