We faced a problem with our Lordmancer II Slack channel. There were many scam messages every day: in private, in general channels, etc. We constantly banned those spammers, but they just registered once again (even the names were the same!). Also each day we saw new members with names like "CEO", "cofounder", etc.
Finally we dicided to close the Slack channel. Now we use Telegram group
https://t.me/lm2ico as a main communication channel.
I strongly recommend not to use Slack for ICO campaigns!
This issue have been known already on where there are lots of scammers who do spread phishing links on that chat medium on which newbie investors do easily fall out on the trap which they do logged-in on those link which are actually phishing links just to get the private keys of the wallet.Using Slack nowadays would really be dangerous on both investors and the project owner.There are lots of alternative though.