Google dropping pages from SERPS

[guy_andrews]

The website for my London based plumbing company has thousands of specifically tailored pages for the various services we provide to all the areas in London. It equates to approximately 6000 pages in total.

When google has all these pages indexed, we tend to get a fair bit of traffic - as they cater pretty well for long tail searches. However, every once in a while Google will drop the vast majority of our indexed pages from SERPs for a few days or weeks at a time - for example at the moment Google is only indexing 613 whereas last week it was back at the normal ~6000.

Why does this happen? We of course lose a lot of organic traffic when these pages don't displayed - what are we doing wrong?

Website: www.pgs-plumbers.co.uk

[Tompt]

I am fairly sure that Pagerank is now constantly updated, it may well be that they only adjust the visible pagerank every three months though.

I can only say this next bit speculatively because I don't have the data (I would love to see the periods and numbers for the site above), but the cap itself might be a somewhat fluid idea, pages may be retained in the index as they are discovered but get pared back to their "hard cap" periodically.

[StalkerB]

Yeah, good shout. I was thinking about that as well, and maybe something to do with switching or upgrading of data centers, but probably not the latter to this extent.

[DavidKauzlaric]

Seems unlikely he would drop 90% of indexed pages and regain them back soon after if it was a PR thing, don't you think? Aren't PR updates generally quarterly?

[Tompt]

I think it could be down to an indexation cap. I know Pagerank is not the force it once was but it does play a role in the number of pages google retains in it's index (if they regularly cull sites back to their cap that might explain the fluctuation, or maybe you fluctuate between two thresholds).

Matt Cutts made some comments which Rand broke down into bitesize chunks in the SEOmoz blog to that effect:

http://www.seomoz.org/blog/an-illustrated-guide-to-matt-cutts-comments-on-crawling-indexation

Your Pagerank is low, and without trawling through your site I don't know about duplicate content, but this could well be it. The fix is the same as an awful lot of SEO problems, more, better links.

[DavidKauzlaric]

I also think it's very possible his previous experiences with rankings dropping and pages getting de-indexed could have been at key algo udpates as well. Mayday, etc...

[StalkerB]

Yup David's point above is the prime suspect for a lot of changes just now, however you say this has happened before?

Are you doing anything else at the times when you've noticed you get dropped for a few days/weeks? Roughly how often does it happen?

EDIT - Just quickly put your site into OSE and you don't have a hugely diverse link profile, plus the sort of sites you're getting links from may have been  effected by the farmer update which is had a knock on effect to your site (and similar updates may have done in the past). Not conclusive but something to think about as well.

[DavidKauzlaric]

The answer could easily be the Google Farmer update. If you are not familiar with this, read the latest post by Rand: http://www.seomoz.org/blog/googles-farmer-update-analysis-of-winners-vs-losers

That will help you understand the latest algorithm update and how you can do something about it.

It sounds like you dropped off due to the algo update and that leads me to believe that Google thought your content was not high enough quality?

I would read Rand's post, evaluate your website, and then have the content analyzed and see if you need to hire a really good writer to build high quality content that is valuable to the users. If you were building mediocre content to target thousands of keywords, specifically long-tail, you need to revamp that strategy and focus on amazing content first!

Hope that helps.