

It's annoying, but that's capitalism for you. With pages built to serve users ads in order to earn the site owner money, it's in their best interest to get you to stay on their page and/or reload the page several times. If you spam the Back button fast enough you can sometimes get in a second click before the redirect registers to escape it. This means that upon loading a page, it will redirect you to another page (or, using an Anchor tag, another location on the same page), but this means that clicking on "Back" just takes you back to the point that it tells your system to redirect you to the page you were just on and are trying to leave, creating a cycle. Webpages can also be set up to do similar things simply upon being loaded in the first place (think that middle step after the login button is pressed being built into the page itself). When you click on "submit" or "go" or whatever they've labeled the button, the webpage will "post" that information to another page which then does something based on that information, which could result in a redirection to yet another page.

One feature of webpages is that you can use them to submit information to other webpages (think simple web forms like username and password boxes).
