A microsite (also referred to as a "minisite" or "weblet") is a website that is comprised of an individual page or a cluster of pages which supplement a company's primary website. The microsite typically will have its own URL distinct from the primary site. Microsites are particularly useful if your business offers a variety of products or services and you want to highlight one segment, individually, for your customers. The minisite offers specialized information on products and can be a permanent place to showcase the product, or a temporary site during a product launch or promotion.
Additional purposes of microsites include:
Providing service or support for a specific product
Listing detailed information relevant to a new product
Creating a keyword-friendly "home" for a new product to improve search engine rankings
Decreasing pay-per-click expenditures by focusing keywords in one place and improving Quality Scores
Increasing a primary site's page rankings by providing inbound links via the microsite