means that the document requested is found however temporarily resides under a different URL. Since a permanent redirect has not been used, the client should continue to use the original requested URL for future requests. From an SEO point of view, it is always better to use a 301 redirect over a 302 redirect as webmasters have used 302 redirects in the past as a black hat technique for hijacking content from others.  The abuse of the 302 redirect worked like this:

This Black Hat SEO practice of using a 302 redirect to hijack content involves a server-side redirect that basically makes the "victim" site disappear while the site with the 302 redirect is the one that actually appears in the SERPs.  The "black hat" site pages are the ones that showed up in the Search Engine Results Pages with the same title and description of the hijacked page but different URL.