You have seen on so many blogs that there is some effects like the texts are italic, bold, underlined,Strikeout,URL's,Trademarks,Quoted Text in some of post that you might link but if you don't know how to add HTML text effect on blog than it seems bad to you, but don't worry.From now you too can add HTML text effect on any blog post , blog comment forum,your own blog post etc.
Italics: <i> and </i>OR <em > and </em>
Bold: <b> and </b> OR <strong > and </strong>
Strikeout: <strike > and </strike>
Underline: <u > and </u>
Trademark: ™ (& + trade + ;) or ® (& + # + 174 + ;)
URL's: The same way you do in your blog.<a href="URL">Text</a>
Quoted Text: <blockquote> and </blockquote>
You can get full list from here.