I know there are many questions around here on how google will treat your site if you change a domain and redirect it to a new one using 301 redirect. For example, if you have www.olddomain.com and want to have www.newdomain.com now. 301 redirect to www.newdomain.com will be the best option to pass links and PR from www.olddomain.com. As I am revamping my domain I have decided to use the new structure and now my page www.domain.com/my_folder/ will be redirected to www.domain.com/my-folder/. I have read that I should use - instead of _ thus during this experiment I will find out for sure if 301 redirect works with google and other search engines. If you have any questions or would like to know what happens to the ranking keep checking the page. Also, if you have any comments please feel free to express yourself. NOTE: my www.domain.com/my_folder/ is on first page of google already for the keyword and thus it is vital for me that google will rank my www.domain.com/my-folder/ in the same way. Hope it will not take long to get the rank back.
This should work just fine, just make sure that there is very little delay between moving the contents to their new URLs and implementing the 301 redirects. There may be a delay likewise in your ability to see the results, but it shouldn't take long.
This depends on various factors (not least your link popularity). Once you have moved the contents and put in the 301, generate a new xml sitemap (you can use xml-sitemaps.com for free) and submit it via Google's Webmaster Tools. This should speed up the process somewhat, but be patient. By the way, until your new pages are indexed, your old pages should remain in the index, so people will keep finding them through search and getting redirected if they click on your URLs. So the delay is not a big deal.
You will lose pages ... I did a 301 at the start of the month and lost a couple of thousand indexed pages , they are starting to come back but only a couple a day.
Thank you everyone. Philip, you are absolutely right that even though the new pages are not indexed the visitors are redirected to the new page when they find old page in google index. The second advantage I have is that my home page ranks higher (for some reason) than the subsection so my ranking for the home page should stay anyway. text links, I thought it was going to take anywhere between 2-5 weeks to get most of the stuff indexed and re-evaluated. And you supported my theory. Thanks. As I understand I will have to keep those redirects forever on my server to make sure all the link and PR juice is passed from the old links. Thanks.