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AFAIK since the way images are used online hasn't 'significantly' changed in decades (as Zohaib says) - there is no factual industry standard. But this technique seems like it could yield faster page-loading speeds for mobile, which we all know Google does stand behind. Google often come up with an error on Page Speed insights which says, you are serving massive resolution images with a tiny viewport. They actually can and do regard that as an error, so surely if Google documents that the technique is acceptable to them and we know it solves certain issues, it is at least 'worth a try' IMO

You can get a quick list of (currently 917) domains in the globe network at the url below which I found by googling the following: inurl:the_worlds_most_visited_web_pages http://www.theglobe.bet/the_worlds_most_visited_web_pages-txt.txt

I agree totally with Chris and according to Matt Cutts: "So if it’s a link from one page on your site to another page on your site, you want that featuring to flow, you want Googlebot to be able to find that page," Cutts continued. "So almost every link within your site, that is a link going from one page on your site to another page on your site, I would make sure the PageRank does flow which would mean leaving off the nofollow." So, just use no-follow for links to websites you don't trust.

Thanks yes - it was a 301 redirect not set up correctly. Regards Mike

We experienced a similar thing when we implemented a live chat solution. Our TTTFB increased siginificantly, not only did this impact the serps but also reduced the customers experience due to having to wait longer. See if your live chat solution can provide you with a gzip compressed version that you can also load in asyncronously. This may help give your site a speed boost whilst at the same time maintaining an excellent UX element.

Ouch! You would need to get some sort of code other than 200 to fire a 404 or 301 would be best as you can direct users, you can also try to block those URLs via robots i suppose, and the third option you can try depending on what you can do is a rel=canonical link pointing towards the correct page which would help all seems a bit manual though might be worth seeing if there is a longer term solution. in an ideal world a 301 would be perfect (or at a min rel=canonical tag).