Is GIG marketing in social media considered as spaming?
Depends on the group and platform. Most groups I’ve seen dissuade self promotion(with good reasons). But, if you can get the right crowd, it wouldn’t matter. You can also directly message the members of a group outside of the group to avoid spamming.
Only if your tactics are exploiting something.
If you Tweet mention your gig to someone that is spamming. If you reply in a thread your gig or otherwise promote yourself, that is spamming.
Promotion is only spam if you are appropriating a space to promote yourself or posting unsolicited things where they aren’t welcome or relevant. No one likes a person who breaks into a conversation to tell them to buy their product.
That being said, self-promotion only helps you if you are also providing value and support in conversation, insights, sharing others’ work, etc.