New link addresses, big site, site map

[asmith20002]

Hey guys

I apology if it is the wrong forum.
I've been reading and searching for like 8 hours and I'm so much confused.

1.I am working on a site, which has about 500,000 views per month. I use friendly (.html) urls. (example.com/news1234.html)

I want to change these urls to pretty ones (example.com/news/1234/)
google has cached about 250,000 pages.

Is there any risk or damage to the site visits if i change all the link address to pretty-type ones?

2. About 100 pages are added everyday. I want to add xml sitemaps. I searched for xml site maps a lot, but i didn't find anything related to sites which grows everyday. I looked up some similar sites and how they set their own, I saw 2 sites (bigger than mine and growing like 300 pages everyday), that they had set a tiny site map that only tells their site categories. like 10 of this in their xml file:

<url>
<loc>http://www.example.com/computer/</loc>
<changefreq>always</changefreq>
<priority>0.9</priority>
</url>

but I have no category, or folder. (don't know if google will count example.com/news/ as a category or not, the real address is files.php?name=news&id=1234.)

I think I have messed it all up. Please help me
Thanks in advance

[tedster]

Is there any risk or damage to the site visits if i change all the link address to pretty-type ones?

Yes, there's a big risk. Google ranks URLs, not "pages". Backlinks go to URLs and not "pages" and that means PageRank is assigned to URLs.

Here are two very informative threads about your challenges - both are listed in the Hot Topics area [webmasterworld.com], which is always pinned to the top of this forum's index page.

Changing URL Structure [webmasterworld.com] - take on tasks in a logical order
Site-wide 301 Redirects [webmasterworld.com] - how long for Google to index?

[asmith20002]

Thanks for those 2 links.
jd01 seemed to have the best result doing such thing.
the thing i'm dealing with is,

I have setup the wildcard subdomains ,So that I could add states and cities. So I put every "info" page in its own state and city.
for example :

www.example.com/news123.html

must be change to :

state1.example.com/city1/news.html

making urls to pretty ones, was an old plan (shame we didn't do it sooner).
So I was wondering if I'm changing urls for states and cities, maybe i change them to pretty urls too , like :

state1.example.com/city1/news/page-title-words-123/

according to those threads,
I'm thinking first I make all new pages that are being added everyday to the new url structure (so no losing old data). and just adding new rewrite rules in htaccess for new structure.

Then making previous data to new urls after some amount of time.

the thing is, new urls can still work with old strucure , for example :

state5.example.com/city10/news/page-title-words-130/

can still work with :
www.example.com/news130.html

doesn't it hurt my rankings?
Any better idea?

[edited by: tedster at 9:59 pm (utc) on Sep. 13, 2008]
[edit reason] de-link the examples [/edit]

[tedster]

Do not let both urls resolve directly with a 200 OK http response - that's what you need to do in order to make the change and not have major long-term problems. Make sure the old urls result in a 301 Permanent Redirect response that redirects to the new style of url.

[asmith20002]

tedster thanks for helping me out.

As it is my first time, I'm so careful about it.There are a few things I don't know what to do, I guess it is because of the new url structure.

1. If on a page i have these links :

www.example.com/111.html (the page title is "1st page")
www.example.com/222.html (the page title is "2nd page")
www.example.com/333.html (the page title is "3rd page")

suppose 333.html is my newest page, which I want to start changing url structure with. So this page will be change to this :

www.example.com/111.html
www.example.com/222.html
state5.example.com/city8/news/333-3rd-page-title/

Make sure the old urls result in a 301 Permanent Redirect response that redirects to the new style of url.

I assume you mean these addresses by "old urls"
how to redirect these :

www.example.com/111.html
www.example.com/222.html

to my new style?
I mean by them system can't find out what those page title is, or what state they are in, so that it could find their new url style to be able to redirect them.

2. I have about 250,000 pages. How many of them I must choose to change their address each time ? (those seems a lot)

3. Is it a big damage if I set 2 urls (old and new) for each page ?
I mean as you see I have a "long new pretty url" and "short old friendly url" . and maybe add "old pages" to the old url page title? ( to make it a little different than the new ones)

I've seen some sites that in their pages, they had written "link to the old version". And when I view the old version I see almost nothing has been changed in that page, but the address. (that's why I asked)