While the NBN will help speed up delivery of large objects like video other files, it will not accelerate delivery of content. Interestingly, the NBN will also change our expectations of how fast websites should load. An accelerated site will be even more noticeably quicker on a high bandwidth connection (like the NBN) than on current lower bandwidth connections.
This is consistent with findings regarding the move to broadband from narrowband. It was shown that broadband users are less tolerant of web page delays than narrowband users. In 2006, JupiterResearch conducted a survey and concluded that 33% of broadband shoppers were unwilling to wait more than four seconds for a web page to load, whereas 43% of narrowband users will not wait more than six seconds (Akamai 2006). These tolerated load times are lower now than they were in 2006 and will be lower again with the introduction of the NBN.
So, the NBN will make websites faster. However, it will deliver the greatest benefit to websites which have been accelerated. Any websites which have not been accelerated will appear even slower relative to their competitors.