When Google, etc. indexes a post, the snippet contains the text on the welcome screen instead of the post text. This is because the search bot isn't logged in and gets the welcome/sign-up header that a logged in user doesn't see. This is a big problem for SEO. Every blog post will have the same snippet text.
Is there anyway to not display the welcome screen if the user is a search bot? To see what I'm talking about, search for "The Importance of Copy Editing for Bloggers" on Bing. It's the first position, but it has the wrong text for the snippet because the welcome text appears before the post text. Unfortunately this degrades the theme's SEO capabilities.