The HTML5 <article> tag is an indicator of a content that can stand on its own. This means that even if that particular content is taken out of the website or webpage, the meaning and sense remains in-tact. There are common instances during which the HTML5 <article> tag is utilized. It is important for creating blogs articles, web content articles, forum posts, online news articles and other web content which involves the use of texts.
The use of <article> tag is not similar for HTML5 and HTML4.01 because it is present only in HTML5 and this is not used in HTML 4.01.
On the other hand, the HTML5 <article> tag is capable of supporting the Global Attributes and Event Attributes in HTML5.
Using the HTML5 <article> tag is not a problem because all the major web browsers like Firefox, Safari, Opera, Google Chrome and Internet Explorer support this tag.