Since April 16th I've been getting alerts regarding a high number of 404s to pages that do exist on our website, but with /mobile appended. For example: www.mysite.com/some-page/mobile
There appears to be a variety of user agents being used, including Chrome and Firefox. IP addresses appear to be from legitimate sources (i.e. the general public).
Any ideas where this could be coming from? Has there been any new technology released that could be looking for these pages, or is there perhaps a tool that someone in the marketing department has installed...
Update: Answering a few comments here:
- The Http Referrer data looks like these are legitimate users. The general activity on the site also makes it look like these are legitimate users - i.e. the number of pages visited and the traversal through those pages.
- There is no consistency in referrers - most are from Google, which is normal, but some are from Bing or other websites.
- Google Webmaster Tools does not indicate any crawl errors for these pages
- No we are not a Tumblr site :)
My guess is this is a browser plugin of some sort...