Using social media promotion isn't really bad thing but considering that even there are lots of people or traffic on it but it wont really signifies that you will able to get huge percentage when it comes to investors since most of those people aren't have the awareness when it comes to crypto investment.I would rather believe that forum advertising is much more effective than on this one.
Having target investors is the real score for advertising an ICO to the forum of cryptocurrencies like bitcointalk. But also there are many people who are not yet aware of ICO's, crypto's or bitcoin in the world but they know how to use social medias. Before it was a good way of advertising because it can get many target viewers that are really gathered by social medias just for the advertiser but some websites now are not allowing ICO related advertisements like in facebook.