Hi @bunnychum, welcome to Steemit :-)

IF STEEM FALLS UNDER THE CATEGORY OF SOCIAL NETWORK OR ARTICLE SUBMISSION SITE ?

I think it's both. The way the site works, anyone can choose to support your post if they think it contributes value to the network. They can also flag it if they think it detracts value from the network. There are no formal rules, because everyone has different ideas about what that means, but you can find various guidelines on what tends to be flagged and what tends to be ok. If you feel that they flagged you wrongly, you can appeal either to them to remove their flag, or to other stakeholders to support your post with upvotes.