Can only edit posts on the main page
If you are logged in as a user with rights to edit the blog, you have edit links for the posts that are currently displayed but anything in the archive is not accessible except on the BlogView.aspx page and there are no edit buttons there.
I am just noting this to myself so I will remember. I will add the edit links to the blog view page so that old posts can be edited. I noticed it today when I wanted to re-categorize some old posts and I couldn't get to the edit view for those posts.