Yes, Social media channels for projects are normally used for announcement concerning the progress of the project, its achievement, partnerships, upcoming developments etc. It is also used for promotional activities including giveaways, airdrops etc. It is necessary for bounty hunters and investors to utilize it well in order not to miss salient information or announcement.
What about here in the forum? A crypto project can post an introduction here and as well as provide updates. Updates can also be done on the projects very own website, and messaging groups but no doubt that social media's still has their own charm. There are lots of people who are using them and they can deliver notifications on our screen quickly.
When it comes to promotional activities and giveaways, I think the forum can win this time. There are campaign managers here to ensure that participants are not abusing the program. Even though we are up to date, sometimes success aren't still guaranteed. This is the only sad part here.