FranticFish... to make this easier to follow, here's a typical result for info:example.com...
Google can show you the following information for this URL:
Show Google's cache of example.com
- Find web pages that are similar to example.com
- Find web pages that link to example.com
- Find web pages from the site example.com
- Find web pages that contain the term "example.com"
It's worth noting that there's a variety of data types, possibly pulled from a variety of "layers" in Google's index.
Regarding this, you asked...
When I query Google with info:example.com the date is 15th April 2016
When I click the link to view the cache for exanple.com the cache date is 30th October.
To make sure my understanding is in agreement with your description, when you say "date" and "cache date", I'm assuming the following...
- that in the 15th April case, you are talking about the date you get when you click
Google's cache as returned by the info: operator, in the top line...
Show Google's cache of example.com
- and that in the 30th October case, you are talking about the cache date you get when you query Google directly for example.com
The cache, as you probably know, isn't generated live from the site displayed in the serp. It used to come from a different data center than the serps did. Now, I believe it comes from a different layer of servers within the Google index infrastructure. I'm not sure their physical location matters much, but their function in Google's index does.
Some layers are updated more frequently than others... and, from the little I know about NoSQL databases, the assigment of layers would depend upon Google's need for the data of different types to be available in various forms, for different types and speeds of computation, etc.
Reporting functions are likely to be a low priority on this list... viz, the least fresh. Consistent with my understanding of what you describe of the info: operator, the cache date might essentially be a cache of a cache... or probably more accurately, the cache date comes from a different data layer than other parts of the cache.
Your report of inconsistencies in the matchup of cache dates and snippets is an interesting observation, I think, about how the data is sharded in Google and then reassembled when Google returns results for this particular operator. What's included in info: is a particularly unusual combination of data for Google, and the anomaly in reporting it is a characteristic of some NoSQL databases... Someone more familiar with NoSQL than I am would need to explain further.
The different caches I just viewed, though, all had yesterday's date... nothing as old as April. To some extent, also, there's likely to be a chance aspect to where in the indexing cycle certain layers are queried and combined.
I should add, btw, that I've never truly understood the point of the
info: operator, but you might be able to explain it to us. Apparently, not all SEOs use it. My first and almost only encounter with the info: operator was in this thread...
"no information is available" message on info: operator search Aug, 2015 https://www.webmasterworld.com/google/4761298.htm [webmasterworld.com]
It was an interesting puzzle, and I remember that results were different depending on www or no www, canonicalized, etc, but it wasn't clear to me what one might pick up from this grouping that caused Google to define it as an operator.