What it is: A subsection of your website, made up of multiple pages. Your microsite should be clearly separated from your main site to form a stand-alone "mini website".

When to use it: If you want a destination for visitors that showcases a specific campaign or a product or service category.  For example, if a museum is hosting a special exhibit, a microsite could be dedicated to this artist, their history and their influence on the genre.

What it's not: A landing page. Although a microsite is dedicated to a specific purpose like a landing page, it goes a step further and gives more detail by using multiple pages to engage visitors.