A microsite is a website that is smaller and is separate from a larger, main site. For example, a camera review site might cover several brands of cameras, so for each brand, there might be a separate microsite. Even though some people think that microsites are great for boosting the authority of the main site and passing on "link juice" to it, there really only are a few instances where microsites should be utilized.
Microsites can be successful for promotions or campaigns that are short term, although it is usually a better idea to market these occurrences on the main website.
Rocket 55, a Minneapolis web design firm, goes over some reasons why microsites are not so effective for SEO:
The Search Engines Want Quality Content
Your site is more likely to rank better in the search engines if you have a lot of quality content. Having only a few pieces of content on several sites is nowhere near as good as having one site that contains a lot more material that adds value to the visitors.
Your Backlinks Are Spread Out and Lose Value
For search engine optimization purposes, it is important to build a wide variety of links to your main site. However, if these links are spread out to several minisites, it decreases the value and power of these backlinks. It's much more effective to point these links towards your money site.
Confuses Customers
Having several sites promoting your business' various products can get confusing for consumers as they browse to make a purchase. It eventually becomes a hassle to go from site to site if a customer is to go from brand to brand. That's why it's important to keep your site structure simple to avoid frustrating your consumers.
Trust with the Search Engines
Chances are that your main site is an aged authority in the eyes of the various search engines on the internet. Adding content to your main site will continue to build upon this trust and authority, while if you were to add this content on separate microsites, it will take a lot more time to build up the value of these microsites and rank them in the search engines.
The Minneapolis web design firm, Rocket 55, believes it's a much better decision to move away from the idea of microsites and continue to promote the brand of your current main site. You will see results much faster and can maintain your current search engine rankings.