Selected answers from the Dumb SEO Questions G+ community.
Greg Baka: I want to add a meta tag to each of my web pages to tell Google when it was last updated. My research shows two different tag styles for doing this. Which of these two is currently the best method? <meta name="revised" content="02/25/2015" /> or <meta http-equiv="last-modified" content="2015-02-25" />
Jim Munro: I don't think either will make a difference, Greg.
Google will always trust it's own data over anything a user publishes. Besides, googlebot already knows the last time it visited your page. Whether you say it was revised or not, googlebot will re-download the entire page anyway (at a time of it's own choosing).
Maybe "revised" is a new html5 thing but I could not see it mentioned on any sites that I would rely on. I could not find it on w3c.
Last-Modified is usually sent as a header response for caching purposes.
You could add <lastmod> tags to your sitemap but I don't think googlebot pays attention there either.
A lot of supposition here. I'll probably regret this response tomorrow. :)
Here's a non-exhaustive list of meta tags that googlebot reads: ;
There are others such as "unavailable-after". This one requires dates expressed in RFC850 format for googlebot to read it, which is why I think the last-modified meta above is bogus.
Mach Page Speed: Hey + ;I would have to agree with + ;your server should be doing it through the header response. The html tags are useless. I will need to find it, but I created a little script that you can plug in your page url to test it.
Edwin Jonk: There are many ways to tell bots when the page was updated. For example or markups.
Furthermore most markups use ISO 8601 for the data format:
Greg Baka: Thanks + ; - I had not considered Schema as a way to pass the "date updated" information. But not sure I can since most of my pages already have Product schema on them and the schema "dateModifed" appears to be only for the CreativeWork category.
I was really hoping to use a meta tag...
Greg Baka: For those curious about WHY? I want to do this, declaring Date information (both created and last updated) is #11 on the "Do" list for behaving as a quality website described in this article themoralconcept(dot)net/pandalist(dot)html (which was also a Moz guest blog)
I'm getting ready to do winter maintenance on my sites and plan to include these Best Practices (and remove one that is on the "Do Not" list)
Jim Munro: Please at least disable that link, Greg, but I'd prefer that you remove it altogether. I reckon the bits he gets right must be coincidences. :)
Edwin Jonk: + ;first please disable the link like themoralconcept(dot)net/pandalist(dot)html
Second, thank Jim because his answer is the best, imo.
Third, please note my comment about ISO 8601. It is important for bots to understand the date format.
Greg Baka: I did some more research after sending my original message and found that although both those meta tags are technically OK, neither is listed as being read or used by Google. (Hat tip to + )
The best solution appears to be using text on the page AND schema markup of text with the Created and Modified data like this:
This does cause the Google Structured Data Testing Tool to display both dates, so it seems safe to assume that Google will at least recognize the information. If they use it or not is always a mystery, but it won't hurt to include it...
Jim Munro: I think it's important to realise that interaction with googlebot is not real-time in any way other than as it requests a file on your site and downloads it in full. googlebot is not guided by anything you do, even a properly configured and accepted sitemap is no guarantee that all urls listed will be requested at all, let alone on the timeframe that you want to specify.
Crawling is managed by information recorded from previous crawls and current user activity on any page. Adding a revision tag will not cause googlebot to do your bidding. Unless your site ;is a WP site or a site with tranches of thin content, I would just give googlebot free rein to crawl and forget about it.
I think your valuable time would be better spent focussing on something else like GA user activity, UX, and asking yourself if your page was the best result available for that visitor.