The unfortunate thing about a 301 redirect is that it sounds so extremely geeky and off-putting to the average business owner that they're scared away. That's too bad, because it is a critical tool in search engine optimization. So, to that end, I'm going to attempt explain the benefits of 301s in the least geeky way possible.
Search Engines and Trust
There are a lot of variables in why one site ranks higher than another site at Google and other search engines. One is how long the site (and a given page) has been in existence, and another is how many incoming links a page has. All things being equal (which they never are), older pages rank higher than newer pages and pages with more inbound links rank higher than ones with fewer inbound links.
Breaking that Trust
Often, when rebuilding a site, you end up changing the URLs–or addresses–of your web pages. Maybe it's because you're reorganizing your site, or maybe it's because you're redeveloping your site on a content management system like WordPress, Drupal or Joomla. In either case, the new URLs don't have the trust that the old URLs do, even if a lot of the content is the same.
It's like moving to a new town. You may have been the greatest manager/plumber/accountant in your old town, but that doesn't mean anything in the new town. You haven't changed; you still have an excellent bedside manner or mad sales skills, but you're starting from scratch in this new town.
When you take your established content, uproot it and replant it somewhere else on your site, you are resetting the clock on when that content was created and breaking all of the inbound links that pointed to it.
Reestablishing that Trust
There are many ways to tell the search engines that you've moved your content, but the most search engine friendly way is the 301 redirect. By setting up 301 redirects for your content, you show search engines where your content has moved from, and your inbound links will now direct to your new pages.
How you setup your 301s may depend on the type of host you have. If you have no idea what I'm talking about, it's time to talk to your web developer and get them involved.
If you want your web developer to create redirects for you, I recommend writing up a guide for him or her to show where the old pages should be redirected. Here's a guide for you to use, where the first item is the old page and the second item is where you want the traffic to flow:
- old/old.html -> new/new.php
- van-halen/david-lee-roth.html -> van-halen/sammy-hagar.html
- wonka/gene-wilder.php ->wonka/johnny-depp.php
If you do feel comfortable playing around with 301 redirects, .htaccess and other files on your server, there are plenty of resources online:
- How to Redirect a Web Page Using a 301 Redirect
- 301 Redirect – How to Create Redirects
- How to Set Up Redirects Using .htaccess
These are just a few of the top results.
301 redirects are also great when you are changing from one domain to another (never a great idea, but sometimes a necessary evil.) Even with a 301 redirect, you should expect a dip during a major overhaul of your website. However, my own experience has been that the numbers get back to normal in about a month or three and then you see increases after that.