If you are a hosting company you may want to stop here because I am going to rant a bit on hosting. This is not a hosting issue in general, but there are specific cases where I become frustrated with web hosting companies.
Take a case which happened today: We have a long term client who is consolidating 2 high traffic sites into one under a new domain. This is a pretty straightforward - the design company takes care of the integration of the content (since it is a new domain with a new look etc.) and the hosting company is supposed to make the necessary hosting changes to redirect spiders and users to the new site from the old sites.