If the only advantage is for SaaS initial load time, then there are other solutions available for developers on a single domain (admittedly more complicated tha

If the only advantage is for SaaS initial load time, then there are other solutions available for developers on a single domain (admittedly more complicated than "link rel=prefetch"). Meanwhile, the downsides and potential for abuse loom large. Most people encounter SaaS initial load time much more rarely than they do web advertising or unscrupulous web developers, and SaaS providers have other ways of more accurately measuring traffic than means which are distorted by prefetching. I, for one, have disabled what little pre-fetching Safari does offer, the "Preload Top Hit in Background" option under Search preferences. No thank you!