Then again, just playing the other side, is it really realistic for us to expect somone who just joined yesterday to know all the formalities and rules of the forums?
Being honest, this looks more like a twitter post or something on social media. They might not be familiar with the interconnectedness of the forums, and might be more experienced in other areas or just not familiar with the norms. (After all, many people like using Tapas more as it creates a platform to connect with your readers.) Moreover, who knows, they might have their own life and different platforms that they have to keep track of as well.
Don't get me wrong, I don't think that just giving an update and leaving is a good thing, but there might be other external factors that we don't know about. I'd still give it a chance. However, as you said, I would approach it with caution.
Just didn't want the assumption that this is a bad thing to rule over the rest of the thread.