How would they know the content hasn’t changed without hitting the website?
replyThey wouldn't, well there's Etag and alike but it still a round trip on level 7 to the origin. However the pattern generally is to say when the content is good to in the Response headers, and cache on that duration, for an example a bitcoin pricing aggregator might say good for 60 seconds (with disclaimers on page that this isn't market data), whilst My Little Town news might say that an article is good for an hour (to allow Updates) and the homepage is good for 5 minutes to allow breaking news article to not appear too far behind.
replyKeeping track of when content changes is literally the primary function of a CDN.
replyCaching headers?
reply(Which, on Akamai, are by default ignored!)
Based on the post, it seems likely that they'd just delay per the robots.txt policy no matter what, and do a full browser render of the cached page to get the content. Probably overkill for lots and lots of sites. An HTML fetch + readability is really cheap.
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