Sort of...? The site will do it's best to keep things in the correct thread or start a new one when needed.? Something as simple as an added space in a subject line may start a new thread instead of adding to the existing one.? If this happens, you can merge the threads.? I think hashtags are typically ignored when comparing a new message to existing threads.
Splitting a thread may be useful when things go off on a tangent.? It does have limitations though, especially when replies are sent via email, so many choose not to use it.? When you select Split from the menu, it will ask you for the subject of the new thread that is being split off.
Duane
Duane