As an internet phenomenon, "FIRST!" posts are very common... and kinda annoying, honestly.
If you are only interested in being first, then posting merely that the content is up makes sense, but then it's just a "FIRST!". There's nothing actually wrong with doing this. It hurts nobody. But as a practical matter it reminds many of fairly juvenile, one-upsmanship posting patterns they see elsewhere.
It should not be worth announcing if the content is not worth discussing. If you are interested in discussing the content, there is no reason why you can't take the time to post, "It is up, and I thought it was cool because..."
I, for one, would take it as a courtesy if people put at least a little commentary in such posts.