Date based archives are not just useless from a usability point of view they don't help your SEO either. As well as possible duplicate content issues if you publish full posts in your archives the main issue is that the pages are full of unrelated content. If you group all your posts about the iPhone together on one page Google can see that the page is related to the iPhone and each post will rank higher because of it. When you group 30 posts from January 2006 together on a page Google just sees it as a page of unrelated content.