levo - 1:46 am on May 11, 2012 (gmt 0)
Be careful to redirect or show 404s
I've recently learned, thanks to new notifications in WMT, that redirecting non-existing pages is a big no no. I thought that soft 404s are error pages with a 200 response, and I honestly believed that leaving as little as possible 404 and redirect them to a related page (or home page as last resort) was a good thing.
As soon as I've started removing 301s and replacing them with 404/410s those random non-existing page requests from Google kicked-in. If it's not a weird bug on their end, I think Google is actively auditing my website for redirections/soft 404s/auto generated content etc.