So, let's say that you have a blog and you decide to change the URL structure within Wordpress. For instance, you could have the date included in your blog posts, followed by the post name. Example: sitename/12/06/2012/blackhat-seo And let's say at a point you decide that the structure is ugly and you want to change it. Also, let's say that you've worked on the site for months and have hundreds of posts up by the time you make this decision. URL structure change example: sitename/blackhat-seo Now, I know that obviously it's going to hurt the incoming links to your site, but is it going to hurt anywhere else? Will it throw your SEO efforts off? How long do you think before you could rebound from the change?