Often it can make copy more difficult to read online. HTML messages that drive top results make use of a few other design-related tactics that are specific for online readers. Embed your call to action URL in each and every image in your promotion. The assumption is that the more links within it, the more likely your prospects and customers will click. Emphasize with the use of bold.
Italics are hard to read online, and underlined text can often be mistaken for text links.
Break up long strands of copy. There is nothing more boring to read online than endless blocks of text that so often weigh down an email message. Create your design with small paragraphs in mind. Make use of columns and sidebars to break up your copy. Make sure there's plenty of white space between the words, paragraphs, and columns, if used.