make sure your sitemap.xml-file is syntactically correct

how important is it?

[Oliver Henniges]

By the fifth of May I incidentally submitted a sitemap.xml-file to google, which contained one single illformed "date-last-changed" - tag. (I forgot the hyphens). My visitor-stats show a constant decline from that day onwards down to only 70% of the normal average daily uniques. I simply forgot to take a look at my webmaster central console after submitting.

Whilst adding a few more pages I resubmitted by the 26th of May, this time noticing the error-report, repairing the file, and now three days later my stats have become normal again.

The whole process may be purely indicental, because a 30% decline is well inside every-day or seasonal abbreviations and not statistically significant, but I'm really wondering whether others made similar experiences.

How important is the well-formedness of your webmaster-central sitemap.xml?

[tedster]

We see reports like this from time to time, and it is almost impossible to sort out whether cause and effect is at work, or just a coincidence in timing. Your report does suggest something beyond mere coincidence -- but who knows. Especially, as you said, "a 30% decline is...not statistically significant."

Does your server log analysis show whether certain search terms were affected? Or is the decline across all searches?

I do have clients who use .xml sitemaps for Google, and as with any technology, they do get messed up at times. I haven't seen any obvious ranking or traffic problems in those periods. Even when Google has your sitemap, they do not restrict the crawl to it exclusively, neither do they crawl every URL on the .xml file. They seem to use it only as a secondary aid for googlebot, so I'd be surpirsed to hear that an error on a sitemap caused extended problems elsewhere.

[Oliver Henniges]

thx, tedster, for bringing this topic up again.

> Does your server log analysis show whether certain search terms were affected?

I cannot tell, because the logfile-analysis my hosting company provides is not very good, actually. I tested my major keywords sporadically, and there was definitely no difference in ranking. If there is any correlation between the sitemap syntax and ranking, it can only affect the long-tail and there in particular the results will be even further below statistical significance.

I could imagine that the accurateness or wellformedness (and existance at all!) of the sitemap xml-file affects one of the hundred knobs of the ranking algo: If the file exists at all, you get a big plus, because google "assumes" you are willing to "communicate"; if the file is illformed over a long period of time, you might get a minus getting bigger day by day, because the algo "assumes" your site is not taken care of very much.

I guess we will never know, unless one of the google insiders comments on this issue.