At the beginning of March 2009, we migrated this website from Joomla 1.0 to 1.5.

We discussed some of the technical issues involved in this blog post, and I'm now going to talk about the Search Engine Optimization angle. I've had quite a bit of experience in moving sites to new platforms and my experience is that the traffic drop can vary from 0% to 75% depending how well its done. For example, the only other Joomla person to publish their data was Barrie from Compassdesigns.net who reported a 20% drop in traffic after his move to 1.5.

Hypothesis

Based on experience, this is what I expect the ballpark figures to be for different kinds of migration.

1. Kept the same URLs: 0% to 10% drop in traffic
2. 301 redirects from old URLs to new: Around a 25% drop in traffic.
3. Broken URLs with no redirects: A 50% or greater drop in traffic

Why do URLs matter so much? I often try to explain it this way .... imagine if you had a coffee shop with a steady stream of customers. One day you shut your doors and moved to the other side of town. Imagine how many of them would bother to travel the extra 20 minutes to visit you. Now imagine that you didn't even put a note on the door telling them where you'd gone.

In Barrie's 20% example, he had a mix of #1, #2 and #3, so 20% was a reasonable drop to expect. He was using Search Engine Friendly URLs and both his 1.0 and 1.5 which is essential to guarantee the smoothest possible migration.

Actual Experience With Alledia.com

Since we launched this site in October 2006, our traffic growth has been very steady:

Let's compare the last two week period before the migration to the first two week period afterwards:

• Green: before the move
• Blue: after the move

We can see a small traffic drop, but let's get some more specific data. Unique visitors are down 7.82%, but those that do come are staying longer and reading 6.52% more pages.

Analyzing the Results

At just under 8%, we were towards the lower end of the 0% to 10% range.

What went right?

• URLs. We used Search Engine Friendly URLs which made it very easy to recreate mostly the same structure in Joomla 1.5
• Data. Using Google Analytics we made a list of my top 100 traffic pages and ensured they worked on 1.5

What went wrong?

• Punctuation. We included too much puncutation in our URLs on 1.0. That produced some old URLs that weren't replicable on Joomla 1.5 (one example)
• Lack of time. Although we checked our top 100 traffic pages, we simply ran out of time to do more. That meant there were a lot of pages where we could only trust that the links worked. We had quite of lot of broken links reported for our less-visited pages. I suspect that is where our 8% of traffic went. If we'd had time to check every page, the number would have been much closer to 0%.

Over To You ...

Do you have experience of migrating a site to Joomla or from Joomla 1.0 to 1.5? Did you traffic drop and if so, by how much? Do you have any tips and tricks for migrations?

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