The holiday season was a disaster for lots of retailers, but the glimmer of good news is that online retail held up quite well:  it is a low cost platform!  Take a look at this post from SEOBook for more on this.

For businesses doing ecommerce in a retail environment (especially B to C), changing product continuously creates a problem for search engines and for the business website’s users. If the site was successful in ranking for a detailed product (classic long tail phrases), those results will continue to draw traffic even after the product is withdrawn.  Result:  404 errors.

Solution A:  301 permanent redirects.  This post in Get Elastic blog takes on the issue of “leaking” link juice due to expired pages. A good solution is to redirect those expired links to  a live page that closely matches the intent or content of the old one.

Solution B:  Where 301′s are not possible (why?) or you’ve missed a page, your 404 page needs to be helpful to the visitor.  I’ve written about Get Elastic’s take on 404 errors elsewhere, but here what you want is a page that helps the visitor find what they were looking for as closely as possible