If that doesn't work usually it's best to address someone with a question.For example, to ask someone a question you may want to use this format to do it and to talk to others the same way: Person's name: Your question Most of the time you will get someone's attention this way.
You can use as many asterixes as you want when typing these out. From hugging an on-line friend to giving someone a cyber-beer to drink.
Also you can use the abbreviations previously mentioned also.
Just keep in mind however that things can happen in a chat just as they do outside. Just as the name implies, cheating can happen on a computer just as in real life.
Just read those stories of married people having affairs on-line.
With IRC chats however just type in the addresses for the person to write down since IRC's are text only and you cannot go from an IRC chat room directly to the world wide web. And after talking with this person for some time you may become attracted to them and vice versa.