1. You have a couple of options when moving a site  or entire site collection to another server  or virtual server (web site). First would be using STSADM tool (comes Out of the box) which can be used to backup entire site collections and all subsites within that collection of sites (webs). This tool will backup all content, versioning within doc libs and lists data, metadata, and all security settings. Your second option would be to use SMIGRATE tool. With this tool you have the ability to backup a single site within a site collection. The only downside to using this tool is that the security permissions will not be restored so those will have to be resetup.

2. When an announcement expires it will not be erased forever but will be simply filtered out of that specific view.

I hope this clarifies your SharePoint doubts!

Thanks for clearing my doubts. But, in my second question, even
after the expiration date  come, the file  is still in the view. Will
it be always there even after the expiration date?