What causes porn redirects on the Web?

Factual Questions
1

So I was surfing a site I often read, via my iPad though Safari. All of the sudden, I see a weird URL, which then redirects to a hardcore porn site.

This is the first time it’s ever happened to me, especially since I normally use Firefox with NoScript and Adblock Plus. I’m unaware of iOS viruses, and as I said, this is a site I visit often.

Could an ad be to blame? Should I inform the webmasters of this site? I don’t think I tapped something I usually wouldn’t, but given this was on an iPad, I can’t be certain (and no, this site usually doesn’t/shouldn’t serve up porn ads).

2

After the iOS 6 update on my iPhone this happened to me regularly on the Dope. Very annoying, but it stopped after a week or so, so the web masters must have done something about it. I would also really like to know what could have caused that.

3

On Firefox, there’s an option under Advanced -> General -> Accessibility to make the browser ask before redirecting you to another page. Is there something like that for Safari?

4

Not that I can see, sadly.

5

It is not at all clear what you are saying happened. Where did you “see” the “weird URL”? Had you clicked something?

6

It’s almost always Javascript. It could be an ad network or a hacked web site - both are common.

If you PM me the URL you were on when it happened I might be able to tell which it was.

If it’s a hacked web site the best thing to do is contact the web host and ask them to alert their customer.

7

Well, it’s certainly got nothing to do with the SDMB ad servers, if that’s what you were wondering.

cough