Posting 1 word responses, information irrelevant to a thread, giant walls of useless information etc is considered spamming, as you have not put thought into your post
Posting in the Welcome section does not contribute to your post count, so posting there isnt considered spam
You can talk to members in a thread, if the conversation is relevant to the threads original post (not off topic etc)
Hopefully this helped, if not feel free to DM me or post below and I can assist further