It is no secret that the attention span of most internet users is getting constantly shorter. The faster your page renders, the more likely visitors are to stick around. If a page takes too long to load you can bet that users will just click on past it without a second thought.
While most users have a much faster internet connection than ever before, there is still a minority that uses a dial up connection. These users will experience painfully slow page loading times if your page is at all graphically intense or has an opening video. Whether or not you want to take them into consideration when you design your site is up to you.
The best estimates are that you have only a few seconds before visitors lose patience with load times. After about six seconds, you will star to have a dramatic loss of visitors. They consider your site too slow or even untrustworthy. If the load times keep your visitors waiting while they click from page to page on your site, the likelihood of them returning to your site becomes almost nonexistent. The average computer user is not using a top of the line gaming computer. They may be besieged by out of date browsers, spyware or a slow connection that makes Flash elements very slow to load.
If you spend some time focusing on better file compression, you can save a substantial amount of bandwidth for every visitor. Getting a faster server is a necessity. If your website server is not fast enough, then your site will be slow to load no matter what you do. Take a good look at the images on your site. If they are not necessary, consider removing them. Images take longer to load than text and while they make your site more visually appealing, they can cause problems for some visitors. If they do not add to the message you are trying to convey, they may not be worth it.
Optimizing both your search engine ranking and your site speed are the keys to increased views and sales. One is almost pointless without the other. If no one knows about your site, then no one will ever see it. On the other hand, even if you rank number one on a search result but your page takes a long time to load, you will lose visitors before they ever get a chance to explore what you have to offer.