Slow Page Load Times Turn Off Consumers and Search Engines
There are many things to consider when a website is performing slowly, and often the web host is not at fault. Any script or widget installed on your website will have a negative impact on page load times. This includes third party analytics, online advertising, or anything that calls information from a third party website.
Often, the more information that is loaded from external websites, the slower your own website will load (not including a content distribution network or CDN). Search engines do take page load times into account for search rankings, although it only accounts for about 1% of ranking criteria according to Matt Cutts from Google.
Still, every little bit helps, and the side benefit is a more user friendly experience on your website.