What happens in this virtual community, is very much like an IRL GTG of friends.
How many times do you meet and chat with friends and stay fully on one topic? with no diversions? before going on to another?
How many times do you finish a GTG or a phone conversation, etc. and say, oh, we started talking about "that" and never continued to talk about "that"!!
Life happens and we get the best from it that we choose.
I wouldn't fret over a thread going sideways, whether ti's your debut thread or one about something else!
Just enjoy the ride!