Micro sites or mini sites are designed to bring special attention to a promotion, activity or product launch. They can step outside the bounds of your main website and narrowly focus on the message. A growing trend increasing in acceptance over the years useful for product launches, contests, virial marketing efforts or user generated content.
Micro sites are also used as landing pages for Search Engine Marketing (SEM) efforts. When a user clicks on a Pay Per Click (PPC) advertisement, they are brought to a website specifically targeting a keyword phrase and providing targeted information. Typically, it results in higher conversion rates for your campaign. Cool, huh?