Difference between 301 Permanent and 302 Temporary Redirect
February 12th, 2010
Permanent 301
They are permanent redirects from an old URL to a new one. These redirects tell the search engines that the old location is to be removed from their index and replaced with the new location. Using 301 redirects is the most search engine friendly way to redirect traffic and engines, and far out weighs that of various JavaScript and Meta refresh redirects.
A 301 permanent redirect will notify the visitor’s browser to update any bookmarks that are linked to the page that is being redirected.
Temporary 302
Here you are telling the search engines to read and use the content on the new page, but to keep checking the original URL first as it will ultimately be reestablished.
A 302 Temporary redirects will not update the visitor’s bookmark.