Why do I often get redirected to a new site automatically?

In this case, the Nike site was redirected to a site of an organization called S11 Alliance, based in Australia.

My home page would mysteriously try to redirect itself to a site called badgurl.grandstreetinteractive.com.

And, for example, many sites will redirect you to a different site that uses different exploits to see if some other location is able to infect you.

Once clicked, the front-end URL redirects the user to a second site.

SuVozonline.com (now redirects to a non-related site)

Some ISPs had implemented the block by redirecting The Pirate Bay traffic to a site owned by the IFPI.

The second attack vector utilizes Advertising network in order to have user click on an advertisement that will, in turn, redirect them to a site hosting the malicious software itself.

Web widgets in which redirection can be co-opted into redirecting to a malicious site.

The Web site Gomperts put up for her newly minted nonprofit organization, the Women on Waves Foundation, was promptly hijacked, redirecting visitors to a site that pictured bloody fetuses.