I just finished a great Digital Web Magazine article about improving page load times with lazy loading techniques. The article (by Jakob Heuser) was very well written and described proximity, timeout, and event based lazy loading. If you continue to read you will see how I was able to reduce page load by 300+kb by implementing lazy loading.
Recently I worked on a project where all member data was being managed through a third party member management service, provided by a company named Avectra. The product does more than manage member data from the looks of things, but all I cared about was interaction with the member management API.