Is there a limit to the number of duplicate pages pointing to a rel='canonical ' primary?

[dsumter]

We have a situation on twiends where a number of our 'dead' user pages have generated links for us over the years. Our options are to 404 them, 301 them to the home page, or just serve back the home page with a canonical tag.

We've been 404'ing them for years, but i understand that we lose all the link juice from doing this. Correct me if I'm wrong?

Our next plan would be to 301 them to the home page. Probably the best solution but our concern is if a user page is only temporarily down (under review, etc) it could be permanently removed from the index, or at least cached for a very long time.

A final plan is to just serve back the home page on the old URL, with a canonical tag pointing to the home page URL. This is quick, retains most of the link juice, and allows the URL to become active again in future. The problem is that there could be 100,000's of these.

Q1) Is it a problem to have 100,000 URLs pointing to a primary with a rel=canonical tag? (Problem for Google?)

Q2) How long does it take a canonical duplicate page to become unique in the index again if the tag is removed? Will google recrawl it and add it back into the index? Do we need to use WMT to speed this process up?

Thanks

[IsaCleanse]

Hey David

Check this MOZ Blog post about Rel=Canlonical appropriately named Rel=Confused? 

[dsumter]

Thanks Sandi, I did..  It's a great article and it answered many questions for me, but i couldn't really get clarity on my last two questions above..

[DonnaDuncan]

Hi David,

When you say "we've been 404'ing them for years", does that mean you've created a custom 404 page that explains the situation to site visitors or does it mean you've been letting them naturally error and return the appropriate 404 (page not found) error to Google? It makes a difference. If the pages truly no longer exist and there is no equivalent replacement, you should be letting them naturally error (return a 404 return code) so as not to mislead Google's robots and site visitors.

Have you looked at the value of those incoming links? They may be low value anyway. There may be more valuable things you could be doing with your time and budget.

To answer your specific questions:

_Q1) Is it a problem to have 100,000 URLs pointing to a primary with a rel=canonical tag? (Problem for Google?) _

Yes, if those pages (or valuable replacements) don't actually exist. You'd be wasting valuable crawl budget.  This looks like it might be especially true in your case given the size of your site. Check out this article. I think you might find it very helpful. It's an explanation of soft 404 errors and what you should do about them.

Q2) How long does it take a canonical duplicate page to become unique in the index again if the tag is removed? Will google recrawl it and add it back into the index? Do we need to use WMT to speed this process up?

If the canonical tag is changed or removed, Google will find and reindex it next time it crawls your site (assuming you don't run out of crawl budget). You don't need to use WMT unless you're impatient and want to try to speed the process up.

[dsumter]

Thanks Donna, good points..

We return a hard 404, so it's treated correctly by google. We are just looking at this from a SEO point of view now to see if there's any way to reclaim this lost link juice.

Your point about looking at the value of those incoming links is a good one. I suppose it's not worth making google crawl 100,000 more pages for the sake of a few links. We've just starting seeing these pop up in Moz Analytics as link opportunities, and we can see them as 404's in site explorer too. There are a few hundred of these incoming links that point to a 404, so we feel this could have an impact.

I suppose we could selectively 301 any higher value links to the home page.. It will be an administrative nightmare, but doable..

How do others tackle this problem. Does everyone just hard 404 a page when that loses the link juice for incoming links to it..?

Thanks

[TammyWood]

In this scenario yes, a customized 404 page with a link to a few top level ( useful) links would be better served to both the user and to Google. From a strictly SEO standpoint, 100,000 redirects and or canonical tags would not benefit your SEO.

[dsumter]

I'll add this article by Rand that I came across too. I'm busy testing the solution presented in it:

https://moz.com/blog/are-404-pages-always-bad-for-seo

In summary, 404 all dead pages with a good custom 404 page so as to not waste crawl bandwidth. Then selectively 301 those dead pages that have accrued some good link value.

Thanks Donna/Tammy for pointing me in this direction..