SEO and lazy loading website content05/21/2013
The link below is a good read for ajax-y websites, especially if you’re going to lazy load content. Lazy loading is a design pattern commonly used in website programming to defer initialization of an object until the point at which it is needed. Lazy loading can significantly enhance efficiency in a site's performance if properly and appropriately used. The opposite of lazy loading is eager loading. Lazy loading has some SEO implications.
If you lazy load content that also exists as a separate page, your content will get indexed if a link is available to the crawler (e.g. a link in sitemap.xml). For example, in DirigoEdge we could create a ‘NewPage’ and link to that page from the home page and the sitemap.xml. When someone clicks on the NewPage link we can override that click event and show the content in a modal or do something fancy instead of taking the user directly to that page. Since that link exists on the page, and that page also exists as its own separate entity, it will get crawled.
Now if you load content that does not exist separately, the link will show you how to provide hints to Google on how to crawl a URL that is ajaxed and technically a part of the current page. The world is going to become pretty ajax-y in the future; features like endless scrolling pages and sliding content in place is already the norm. Do yourself a favor and read this article: https://developers.google.com/webmasters/ajax-crawling .