Try not to yell, this is where you either type in all capitals or use text editing to increase the font size and bold type of your message.
Also you can use the abbreviations previously mentioned also.
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.
It just might be what we call in cyberspace, cyber-love.
For a much bigger list the WBS Chat Book has a whole list compiled from various users from all over including various smileys!! If you choose you can use text editing to increase the size of your text to catch someone's attention.
This is most of the list from that place: AFAIK As Far As I Know AFK Away From Keyboard ASAP As Soon As Possible BBL Be Back Later BBN Bye Bye Now BBS Be Back Soon BEG Big Evil Grin BF Boy Friend BRB Be Right Back BTW By The Way BWL Bursting With Laughter C&G Chuckle and Grin CID Crying In Disgrace CNP... This can make your messages in bold, italics, or color.
All I can say is, cheating through a computer is ridiculous, but unfortunately it happens.