Around 2pm today, I found that attempting to display Google Reader caused a redirect to a Google Docs login page – more specifically, a signin page for Google employees (Well, I assume so – it was insisting on an email ending with google.com!).

Looking on Twitter I found only a couple of other people reporting it, although one person mentioned it in relation to a blog from Google SEO expert Matt Cutts. I also follow his blog feed, so I guessed it was related.

Google Reader would briefly display so I clicked on the first unread item title – this caused the feed entry to open seperately and mark the feed item as read. Eventually I got down to the Matt Cutts feed item and, after clicking on that, my Google Reader worked perfectly again. I sent details of the workaround to those on Twitter reporting the same problem.

Matt Cutts has now stated..

Doh! Sorry about the redirect on the most recent blog post. Should be fixed now

The post itself contains a video and, possibly the cause, an embedded Google Docs presentation (did he originally have it pointing to a protected document?).

But this obviously raises a question about security of Google Reader. How is it possible for a news feed to cause Google Reader to, effectively, stop working and divert to another web page. Is this a vulnerability that could be exploited by spammers, for instance?

I’ve sent a Tweet to Matt Cutts and will report back if I get any further details.