How important is the lastmod field in the sitemap?

Selected answers from the Dumb SEO Questions Facebook & G+ community.

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  Josh Levenson: What you see is that G may be more discriminating about indexing page quality.
  
  
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  John Gosling: Josh Levenson maybe, but I`m pretty confident on page quality. The site has scope and detail unmatched on its subject. It`s very niche. I`m top or within top 3 on Google on pages it has indexed, though equally it can be frustrating on some pages. But that`s for another post
  
  
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  Zachary Toto: With over 98% of the market share, Google has a lot more work to do than the others, so yeah it`s going to take them a lot longer to process things.
  
  
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  John Gosling: Zachary Toto so does that imply Bing for instance doesn`t find as many sites as Google? I do have a bing account for the site, but I did nothing (don`t think you can) for duck duck go, and it picked up my site very quickly. Appreciate of course Google is effectively the only game in town that matters, but just frustrated and intrigued that it is so slow compared to others?
  
  
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  Zachary Toto: John Gosling I wasn`t implying that the smaller ones don`t pick up as many sites.
  
  
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  John Gosling: Zachary Toto thanks for the clarification. I should have mentioned in my opening post, bing picked up the new pages I posted just before Christmas in about 48 hrs and had them showing in SERPs, so if all the search engines are doing much the same in terms of process, it does imply Google is slower, and even if they are the biggest search engine in terms of users, you`d think they would be much more scaled up to deliver quick indexing than say Bing, or at least maintain equivalence.
  
  
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  Zachary Toto: John Gosling It can also be a lot easier to rank higher in Bing than in Google. They`re all trying to achieve the same basic goals, but have their own ways of going about it. This could be a factor in why it takes Google longer to index.
  
  
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  Tim Brownson: Zachary Toto It`s actually under 90%, but even so, as John alluded to, that doesn`t mean Bing (or others) ignore other sites. At least I don`t think so.
  
  
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  Stockbridge Truslow: "Quality" is a term Google uses but it doesn`t simply mean "Good Content" - Quality is a combination of things, like whether or not the page has good clear technical signals like Semantic HTML to define page sections/blocks, or maybe it`s having a decent link profile feeding it, or maybe it`s having some known entities on the page along with expected word vectors to help Google understand what the content is about.
  
  Machines don`t look at copy like we do when we read a book and say, "Hey, I love this!" What they do is try to make sense of it all and then maybe see if other pages and sites on the web tend to agree with the extracted sentiment.
  
  For humans... quality is a subjective thing. For Google, it`s objective.
  
  
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  John Gosling: Stockbridge Truslow I`ve built the site on (I hope) sound SEO principles. I`ve run it through the seobility service and it gets high marks. Only thing I can`t control is server speed (it`s on the Weebly platform) which seems to underperform.
  
  
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  Tim Capper: Google is currently super slow with new content
  
  
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  Richard Hearne: Tim Capper I think that really depends on who you are. For the News sites I work with there`s no problem with indexing speed.
  
  
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  Neil Cheesman: Have you tried manually submitting ir or resubmitting it?
  
  
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  John Gosling: Neil Cheesman just tried a page. Will watch how quickly that works, or if at least jumps the queue on the other pages that are languishing.
  
  
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  Richard Hearne: Does your site automatically generate site-wide links to latest content? You might find that internal architecture can play into how fast content is picked up.
  
  
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  Sadat Rayid Odowa: Richard Hearne is it good to have site wide links?
  
  
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  John Gosling: Sadat Rayid Odowa reading up on it, not particularly. Though not 100% certain of the definition.
  
  
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  Richard Hearne: Let`s say you`re a news site, and you include a feed of the latest posts site-wide. This would give Google a strong indication of what to crawl/index. The same principle applies to your navigation links (which are essentially site-wide links - just FYI).
  
  The more "importance" you can signal to Googlebot about your content, the better/faster you`ll see them crawl and index content. Ignore "site-wide links" (I just included this as an example), and instead focus on what signals you provide around content importance.
  
  
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  Richard Hearne: This really depends on your tolerance for out-of-date content cached by Google. If getting the most up-to-date content in Google matters, then having the correct lastmod date in XML sitemaps will help. Googlebot may also start ignoring your lastmod dates if they find no updates to your content to correspond with the false lastmod dates.
  
  But I`m not really clear how this issue can affect recently published pages? Those lastmod dates should be near enough to the pubdate? What TTL values are you setting for HTML pages in your caching layer?
  
  I doubt the lastmod date value is the reason your new pages are not getting indexed faster TBH.
  
  
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  Allan Wicks: Richard Hearne thanks for your thoughts! Checking with developer I wonder if we have issues elsewhere, will update on our progress…