Also, you can use the "Quote" drop-down box.
In addition to the WeeTag that Steve mentioned, you can use the Quote dropdown below the "Process Wee Codes" checkbox on the reply screen.
Just highlight the text you want to quote in the message you're replying to. Change the "Symbol" dropdown box to "Block" and hit the Quote button. It'll build the HTML for you and show you a preview of the result - a blockquote section with the blue line on the left side.
Experiment with the other drop-down choices.
HTH.
Cheers,
Scott.
