My custom permalink structure is /%year/%monthnum%/%postname%.html. When I write "site:mydomainname.com" in the Google toolbar, i see lots of links to my post pages with a different permalink structure than the one set in wp. I don't understand why. It's even as bad as Google Webmaster tool is showing me 13 404 errors to post pages. but when i check these pages, they show up perfectly on Google.
Since I am working on SEO, I would like to know if this custom structure above is good for SEO.
I want to add your attention that I migrated my blog from blogger to wordpress and in case i change my permalink structure, I will have to do a redirect page per page from blogger to wp.
I am waiting for your help. Thank you in advance. Oh! by the way, i am not that much geek so please, if there are technical tasks to perform, please give detailed explanations.