The SPT tag and Splintertalk tribe was set up by the developers of the blockchain game Splinterlands.
This tag is used to help distribute SPT tokens through a rewards pool to players talking about the game.
When you use this tag in your post whales of the SPT tribe will downvote where the featured content has no relevance to the game and or community.
This is to ensure the Splinterlands tribe (Splintertalk) is free of posts not related to the game.
In the future I would recommend not using the tag #SPT unless you’re talking about Splinterlands.