Yes, if you "walk" into a chat room and an existing conversation is taking place, you're welcomed to say "Hi" to your friends and such, but please respect the conversation taking place. It's the same common courtesy you'd have if you did so in real life and joined a group of people chatting at work, at a party or in a support group.

Sometimes such conversations may be really important to the members involved. Listen in for a few minutes, and then decide whether the conversation is one you're interested in or not; move on to another room if it's not.

Thanks for your support,
DocJohn