A Microsite is a limited engagement website. By limited engagement, we mean that its a website, but for a specific audience (a segment of your customers, fans, prospects, etc.) highlighting a specific product/service (usually one product/service or line of products/services), intended to run for a specific period of time (product launches, events, etc.). Microsites are quite popular becasue they let you get wildly creative and engaging with your audience.
Microsites quickly get to the point, and in often a more flashy way. Many Microsites incorporate a whole lot more graphical effects (Adobe Flash, Microsoft Silverlight, and even HTML5) combined with video that simultaneously give them higher engagement.
Done correctly, micro sites inform and engage your audience about a specific product or service that you have or are launching. They’re often more effective becasue they have that focus and speak to the target audience very specifically with calls to action that lead the way to sales, registrations and inquiries.