I think Google tries to fetch any page starting from the homepage down the tree of pages. But how should Google know how deep an url is in your page tree?
It seems pretty pragmatic to me to use the length of the url as an indicator. The logic could possibly be that with every added directory /a/b/c in the url you hit a page deeper down the tree.
This is only a rule of thumb but makes perfectly sense, as google fetches only a limited number of url per domain and the deeper a page lies on yout domain the less important its content should be.
What do you think?
In my experience, Google follows this crawling pattern when all links are of equal value and there are too many links on a page to crawl them all (e.g. most of your state pages). I have several local directory style sites so I've seen this pattern many times.
Just curious, where did you get the public school information for this site? I'm always looking for good quality local data sources.
Hi Russell,
Interesting.
I believe It's because of your site's internal links & hierarchy:
home - links to: home/state - links to: home/state/city - links to: home/state/city/school-name
The spider will follow all of the links on each level before going deeper, following your hierarchy. I imagine your chart looks flat because all states have about the same URL length. To test this theory, find a city/school URL that is shorter then a /city and see if that gets crawled first. You could also test the internal link theory by linking to a long URL on your homepage, and watch the spider hit that first.
P.S.
I have a client who does lead generation for education, I run their SEO program, and I could make use of this set-up. I'd also be happy to share some SEO advice. If you're interested, get in touch with me: anthony@42metrics.com.
Have a great day.
Given the graph, it is clear to see it is not getting the entire set of urls first and then sorting them, so it is not actually attempting to crawl shortest urls first. It is just crawling based on the structure of the website, which happens to be that further depth links have a longer url, and so it is a breadth-first search as expected. This type of search is completely usual for a crawler, and how I would write one too. The observation that it somehow is crawling the shortest urls first is mistaken, it is just following the structure of the website as you can see in the graph.
Site structure could be one reason Googlebot crawls shorter URL's, another would likely be a measure of quality. Often dynamic URL's from search strings and deep navigation are not as important as cleaner SEO friendly URL. Google's click tracking studies have shown time and time again that CTR drops as URL length increases. Google wants to index the most friendly URL's first obviously.
JonnieCache 1 day ago | link
There is probably some highly non-obvious reason that sorting your queue of URLs by length is optimal, which was arrived at after a lot of modelling and testing. We're unlikely to ever know the answer unless someone from google explains it to us. reply
JonnieCache 1 day ago | link
Thinking about it more, its probably just a breadth-first search. Duh. reply
frisco 1 day ago | link
Breadth-first search means crawling all of the links on the page and adding all of the links on the child pages to the queue at once rather than drilling down on one link-path first before moving to the other links on the first page. There's probably some highly non-obvious reason for crawling by url length. reply
xyzzyz 16 hours ago | link
The thing is, the deeper you are, the longer are the urls, so if you do a breadth first search, you are more likely to visit short urls first. reply
AshleysBrain 1 day ago | link
It's probably just a short URL is a heuristic for an important site. www.site.com/section is probably more important than www.site.com/section/subsection/detail/page/5/comments. A good move for the crawler - don't get distracted by "deep" pages - try and stick to high level ones first. Edit: this would also encourage webmasters to use short URLs, which benefits users by being easier to remember, too. reply
orijing 20 hours ago | link
How well-known is this to webmasters? If it's not well-known I cannot see how the second part could be. But the first could very much be true, and is what I would've surmised. reply
cma 1 day ago | link
I don't agree with the last point; seems like it would encourage things like foo.com/1hu83FG2 or lead to excessive abbreviation. reply
DrJokepu 1 day ago | link
If I remember correctly, your page ranks better in Google if the search terms are in the URL (even more so if they are in the hostname). reply
AshleysBrain 1 day ago | link
Well, it's just a heuristic. Also, would you consider that level of abbreviation for your own site instead of descriptive names? You do want users to be able to remember URLs if at all possible... reply
arn 1 day ago | link
I noticed this behavior also when I was following Googlebot's crawl of my old pages after I had done a redesign. it's not because of sitemap or because of url structure or because of dynamic content. Mine were blog articles in the same format. This is how it was crawled: sitename.com/year/mo/day/stub sitename.com/year/mo/day/stub-one sitename.com/year/mo/day/stub-one-two sitename.com/year/mo/day/stub-one-two-three sitename.com/year/mo/day/stub-one-two-three-four reply
orijing 20 hours ago | link
The question that I have is whether this is a relative behavior (i.e. whether, for a given domain 'domain.com' Google prioritizes domain.com/short-url over domain.com/longer/url.html) or a global one (i.e. prioritizing short.com/url over very-long-domain.com/nested/pages/hierarchy.html, all else equal). I can definitely see the local/relative effects being a natural consequence of prioritizing by pagerank, but the global part sounds more like a separate signal. Does anyone have insights? reply
esryl 1 day ago | link
The site adheres to a strict url structure. /state/city/id/schoolname - entering from the homepage, the only way to crawl the site 1 level at a time would be crawling the shortest urls first. this structure is also emphasised in the breadcrumbs on every page, the shortest urls are also the ones with the most internal links. why would you crawl the site in any other way? reply
underdown 1 day ago | link
"why would you crawl the site any other way?" I could see crawling pages most likely to have changed first as those pages would most likely lead to fresh content. reply
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3 points by foxhop 1 day ago | link
If you look at a particular city page you will notice that the cities are in alphabetical order, however google bot still crawls by length of url... reply
personalcompute 1 day ago | link
I did a more scientific analysis of the googlebot requests in the provided log (graph! http://i.imgur.com/uMoUT.png) and it definitely looks like it is taking shortest urls first. Anyone else with a large site want to check as well for further data? reply
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1 point by foxhop 1 day ago | link
Thanks for the graph, I've added it to the blog page reply
meow 1 day ago | link
That's probably because short urls usually tend to be static pages while long ones tend to be dynamically generated content. reply
personalcompute 1 day ago | link
His entire site that he observed this behavior on is static. reply
jules 1 day ago | link
But Google doesn't know that. reply
_grrr 1 day ago | link
A poor mans PageRank algorithm, assuming nothing else, would assign a higher PageRank to shorter site links on a page. Presumably the crawler visits pages with a higher PR first. reply
TuxPirate 1 day ago | link
Pagerank determine crawls rate amongst other things. I find it is also likely that short URLs (especially in the case of a directory-type site) are seen first by the spider and that this order is respected by the crawler (FIFO). You can also ask in #seo on irc.freenode.net I know there are knowledgable SEO people in there who might be able to provide you with a decent answer. reply
ignifero 1 day ago | link
Maybe because that's how they are sorted in the hashtable/database they use to queue urls? Or maybe because they want to index the shortest pages first, so that they are processed before any duplicates with longer urls (i.e. get /articles/ before /articles/index.php) reply
georgemcbay 1 day ago | link
I suspect you're on the right track with your first guess. Most people posting here are looking for some sort of deep meaning in this when IMO it is more likely just due to a localized side-effect of doing something such as storing the urls in a trie-like structure and then iterating over it breadth-first. reply
christianwilde 1 day ago | link
I imagine that in these specific case is because longer URLs represent deeper pages on the site that are less "important" (in terms of internal incoming links and pagerank) than the shorter ones. It doesn't seem logical that google order the URLs by length and then crawl them in that order; probably the URL length can be a factor that the bot takes into account, but not the only one in the manner this article suggest :) Anyway, good point, that deserves more testing to extract some conclussions reply
TuxPirate 1 day ago | link
Pagerank determine crawls rate amongst other things (http://techpatio.com/2009/search-engines/google/matt-cutts-g...). I find it is also likely that short URLs (especially in the case of a directory-type site) are seen first by the spider and that this order is respected by the crawler (FIFO). You can also ask in #seo on irc.freenode.net I know there are knowledgable SEO people in there who might be able to provide you with a decent answer. reply
abrudtkuhl 1 day ago | link
It starts at the top of your sitemap - which are likely shorter URLs reply
bauchidgw 1 day ago | link
cant confirm this - sitemaps are used for discovery -> the urls listed in the sitemap get pushed into the 'discovered urls queue' then this queue is prioritized for crawling- and - if there are no other factors - the shorter urls get prioritized higher (as there is a bigger chance that a shorter url is a canonical version of a longer url - well, the chance is bigger then the other way round reply
I downloaded your data and found many examples where long URLs were crawled before short URLs. I don't know why you would think there was a pattern. The graphic is cute but doesn't show how the crawlers skipped around your link list rather than follow the pattern on your root URL (which was fetched along with the favicon.ico file many times before anything else was fetched).
You don't indicate when links started appearing to the site, where they appeared, or provide any helpful information that might pinpoint when and how Google learned about the site.
So the only explanation that makes sense for what you have perceived is your relative inexperience in analyzing crawl logs and patterns.
All the pages were created at the same time.
The 'cute' graph (not graphic) displays the length of the resource "get" urls in the order that google bot fetched them. There is obviously a pattern in the graph related to length.
Of course there were some urls fetched first that were larger than others, but that is just some chaotic abnormalities among the data. The pattern persists regardless.
Attacking my experience does not help your argument.
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