Starting around Thursday, 9/19/2013, Google Analytics has been showing about 50% fewer visits from Safari users than the Thursday before that for Grooveshark. (Aside: by default we compare each day to the same day of the week from the previous week because usage patterns for when people are on Grooveshark are highly dependent on what day of the week it is. The way people use Grooveshark is most wildly different comparing weekdays to weekends, but even a Monday session is very different from a Thursday session)
I suspect it’s related to a longstanding issue as explained in these 2 blog posts:
http://sunpig.com/martin/archives/2010/01/08/how-to-detect-a-page-request-from-safari-4s-top-sites-feature.html
(2010!)
http://blog.splitwise.com/2013/05/13/safari-top-sites-pollutes-google-analytics-and-mixpanel/ (2013)
it appears that the GA team is finally detecting these “preview” loads and not counting them, although I have not been able to get official confirmation of that.
The evidence:
It’s not just happening to Grooveshark:
Google Analytics Forum question
Superuser question (deleted: google archive)
Another forum post asking about the drop
- Average visit duration is up by 163% for Safari users. That makes sense because the Safari preview visits would by definition be extremely short.
Our bounce rate for Safari users is down by 82%. We had previously determined that Safari preview visits were all being counted as bounces, artificially inflating that number for Safari users. - I also dug into different Safari versions, and at least for the 3 most popular versions on Grooveshark (all that I checked), the % drop in visits is the same, which strongly implies that this drop is not due to some recent update from Apple. We also tested the site to make sure that everything still appears to work in Safari, and we have not seen an uptick in complaints from Safari users which we would expect to see if we had introduced a Safari-breaking bug.
- New vs Returning: GA reports that “new” Safari visitors are down 36%, while “returning” Safari visitors are down a whopping 57%. This also points towards the Safari preview issue because users who visit Grooveshark more frequently are less likely to be considered new and are more likely to have Grooveshark show up in Safari preview.
- Pages/Visit by Safari users is up a whopping 76%. This makes sense since a “preview” visit would only hit the homepage, but real users are very likely to visit other pages.
Note: Grooveshark’s numbers are generally considered proprietary, which is why all the stats above are in relative percentages. Sorry if that made it harder to follow.
I have reached out to Google Analytics via twitter and also commented on the Google Analytics discussion thread, but we have not heard any official word yet. Ideally this would be the sort of thing we’d hear about from Google directly before it happened. Barring that, it would be nice to see a blog post from them about it, which also hasn’t happened yet.
Unrelated:
On the off chance that I now have a Googler’s attention: a probably unrelated issue that we see for the day of Friday, 9/20/2013 is for that day our stats are mysteriously low and internally inconsistent. Visits for that day are 50% lower than the previous Friday. Our internal bandwidth and user activity #s look normal for that day. If I look at New vs Returning, we had significantly more returning visitors than we had total visits…how could that even be possible?! We have seen anomalies like that before but they usually only appear for a short time and are corrected a day or so later.
