do both: submit new sitemap (remove old) and add 301 redirects for a while
make sure to keep checking crawl errors to fix a broken link or similar issues
I'm seriously thinking of converting one of my sites from plain HTML pages to Wordpress. At the moment the site has around 300 pages so this isn't a small project, but in real terms the site has few backlinks and only a PR1.
If I change to Wordpress I could care less about most backlinks since they are to the domain rather then pages, and I could care less about the PR1. But I do care very much about pages being indexed.
The site already has a sitemap, and of course there is a sitemap plugin for WP, so do I actually need to add 301s in htaccess, or can I rely on submitting a new sitemap in webmaster tools?
I'd really appreciate a reply from someone with actual experience of doing something like this who can advise me.
Surely you can make sure that the new Wordpress versions of your pages are at the same URLs as the old versions? No? If you do it quick enough, Google won't even notice.
OK, so I have no experience with this.
I definitely recommend 301'ing old URLs to new URLs.
But, with 300 pages... I'd be tempted to only 301 pages with inbound links.
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This is absolutely a no-brainer. You should definitely 301 redirect your old URLs to the new URLs. The search engines are going to continue to crawl those old URLs because they are in their index. Google will eventually drop them after so many crawls and getting 404s. Other engines will leave those old URLs in their index for a LONG time. So you're going to continue to see 404s in your server logs for a long time causing a lot of "404 noise" which may disguise REAL problems with your new site.
It's a piece of cake to get a list of all of your current URLs.
1) Download and install Xenu Sleuthe (it's a free crawler).
2) Be sure Options/Preferences/Maximum Levels is set to 999 so it will deep crawl all URLs on your site.
2) Crawl your web site with Xenu (File/Check URL)
3) Export the crawl data to a tab delimited file that can be loaded into an Excel spreadsheet (File/Export to TAB separted file...)
The crawl data will include all of the URLs that were found while crawling the site as well as other useful data (title of page, HTTP status returned like 200, 301, 302, 404, etc).
For example, knowing about existing 301 redirects on your sites will be useful because you should avoid/eliminate stacked redirects as part of implementing your new redirects. If you already have URL A --> 301 redirect --> URL B and now you need to redirect URL B to your new WP URL, you don't want URL A-->301 redirect-->URL B-->301 redirect-->WP URL. You want 2 redirects URL A-->301redirect-->WP URL and URL B-->301 redirect-->WP URL.
If you're clever, you can the Xenu data to create an Excel spreadsheet w/ old URL and new URL mappings. Then you can write an Excel macro that builds your rewriterules and writes the needed .htacces file(s) to your hard drive so that you can upload it to your site.
There are a lot of other things that you should consider before starting on a web site redesign. Perhaps a recent post on my blog about web site redesign and SEO will help. Good luck.
PS: Submitting a sitemap is NOT necessary. It does nothing for you unless you want to prioritize which pages get indexed. A 300 page site should NOT need a sitemap assuming a crawler-friendly site. Sitemaps are only useful for huge sites that have hundreds of thousands or millions of pages or sites that are NOT crawlable for whatever reason. The search engines will discover your new URLs by crawling your home page (whose URL should NOT have changed) and by following inbound links, discovering the 301 redirects, and then discovering the new pages.
Sitemaps don't get more pages indexed and they don't get you indexed faster.For most sites that are crawlable the only "real" purpose they serve is to tell then engines, "When you get around to crawling my site, crawl and index these pages first. If you still have room in your index for more pages from my site then crawl andn index these pages next. If you still have room in your index for more pages from my site then crawl andn index these pages next... etc."