I've seen a few SEO consultants recommend using 301 HTTP redirections to forward traffic from an old location to a new location. It seems logical enough, since that's what it's for (301 - Moved Permanently). So I tried it out when I moved a personal website. I can now say that based on my own experience, using 301 HTTP redirections guarantees nothing :)
why try this?
I decided to try using 301s after one consultant in particular insisted that it was absolutely necessary to avoid losing whatever pagerank the old location had; and it would "ensure the site did not lose standing" in search indexes.
Well I know that consultants don't actually have some secret society with the search engine companies, so they're going on guesses and anecdotal evidence. Maybe they're educated guesses and maybe they're total crap. Depends on how ethical the consultant is.
So I decided to try it out myself, since I'm not getting paid to say it works. I didn't have a specific expectation, I just decided to See What Happens™.
For quite some time, the site in question was the third or fourth result on Google for its most relevant keyword. Unfortunately I wasn't checking the public Google PageRank before the move.
The site has some (basic, ethical) SEO techniques including meta keywords (for what they're worth) and a couple of extra keywords included in the
<title>. Otherwise it's just accessible XHTML.
the first move
The page has been moved before using nothing more involved than pages with links to the new location. The user had to actually click through. There was no noticeable dip in traffic to the site during or after the move.
the second move
Eventually I decided to move it again, which is when I decided to use 301 HTTP forwarding like the SEO guys tell people to do. Not having access to the server config, I just plunked a .htaccess file into the directory. In that .htaccess, each separate file had a forward to its specific new home.
The new page (targeted by the 301 redirections) bombed out of Google, dropping from the top ten to the bottom of the top 100. The tenth page of results, aka oblivion :) Pagerank dropped to 1 or 2, depending on when and where you checked.
Eventually I removed the .htacess file and just put up a click-through forwarding page. A few weeks on, it's back in the top ten to fifteen on Google and its Pagerank has rallied to 4 (which seems to be about average for any site with even a little traffic).
what went wrong?
Well, this was hardly a scientific test so there are a few things which may have gone wrong.
- I may not have set up the .htaccess properly
- Maybe specifically sending each page to its new URL is bad.
- There were three variations of the old index filename forwarding the new index URL - maybe that's bad.
- Using 301 in any manner may trigger a bad ranking.
- Using 301 to forward an entire site to a different domain may be a bad idea; perhaps you should only use them within the same domain.
- Other factors may have been to blame and the 301 was coincidental.
No matter what, it seems reasonable to say that using 301 HTTP forwards does not guarantee that you'll keep your old search ranking. Even though using 301 is correct according to the HTTP specification, search engines don't simply swap the URL for the new and keep the current rank/index position of the old URL. My guess is that the new site either starts from scratch or - I think more likely in this case - it gets ranked lower than the old one and has to recover from the penalty.
Considering the page went back to the top ten basically right after the 301s were removed, I think the page was getting a negative flag due to the 301s. If I'm right, it's really a pity that unethical usage has ruined yet another useful technology on the 'net.
so should you use 301?
Maybe. But I would only recommend you do it if the usability benefit for your target audience outweighs the risk of dropping in search rankings. I'd guess that using it internally (ie. within your existing domain) is probably fine. Just don't think it will guarantee you won't lose search ranking!