Has this site been hacked????
 

I haven't seen anyone else reporting this in AudiWorld. Are you clicking a link in Mail? Looks like a URL is being clicked in a message. Check your email settings. Otherwise your email app may have been hacked - I don't believe this is an AudiWorld issue. It's possible the only solution may be to restore the phone.
BYW, I have seen these types of messages in my mail occasionally. I just never open them and delete to the Junk folder. I suspect if they are clicked to open once, it installs a small hack that automatically opens them when a similar mail message is opened even if the link is niot selected..

Nothing to do with email. it's happening at random when browsing the site on iPhone / iPad. I'm not clicking any links. Desktop isn't effected. It's only happening when viewing this site.

Look at the app notation in the upper left hand corner. It shows the Safari website was originated in mail. As I mentioned, you may have triggered this behavior previously in your mail app. No one else is experiencing this at AudiWorld that I've read.
You could also try deleting your cookies and web data in Mail and Safari in Settings. Good luck.

Thats only because I'm clicking a link in an email from AudiWorld for the thread that I've subscribed to. Once I open and start browsing, this pop-up occurs at random. How would my mail app cause that behaviour? It also happens when browsing the site straight from Safari. Very unlikely that Mail or Safari could be compromised - doesnt tend to happen on iOS.

However having just tested it on my phone, it's no longer happening.

@snagitseven and then there were two... can you get admin to investigate this?

I've seen this behavior on a variety of forums using common forum software on iOS (my iPhone in particular). This occurred not only on this forum but some others. It doesn't happen anymore on my Android phone, nor on my Macbook Pro running OS X. It's certainly some kind of bad advertiser on Google that is exploiting the browser and platform (WebKit in particular I believe). Get yourself a good ad blocker installed on your phone; you're going to experience this on other forums and sites that use Google advertising.