MWpro - 1:57 am on Jun 27, 2010 (gmt 0)

piatkow was referring to browsers' default settings, which has links underlined, unvisited links in blue, and visited links in purple.

I don't agree that it is necessary to leave it to the default settings because sometimes a site design mandates something else.

Instead, my rule of thumb is to significantly distinguish the link from surrounding text. For links in paragraphs of text, I always underline to help accomplish this goal. Additionally, a different color than surrounding text is a must.