-
Well what do you know, we have a 6+ million record database table mapping IDs from the old to the new.
301's are being used correctly, so it's not harming PageRank. But Google do detect change and are spidering at around 400k pages per day right now, and there has been a significant drop in traffic from Google (visible in Webmaster Tools and Analytics) since the change.
Who knows how Google works, but the current hypothesis is that Google slow down the referral rate (reduce the amount you appear in search results) when it detects major disruption to the URLs it's sending people to.
I think they basically have a quality measure and want to be sure they're sending people to an actual result.
I also think it's possibly an anti-spam thing... to detect and limit the impact of sites that lose their domain names and bad actors 301 everything to spammy stuff.
We can only wait and see. If we're hit badly, we'll raise the priority of creating sitemaps (which we're not doing right now).
You are reading a single comment by @danb and its replies.
Click here to read the full conversation.
Velocio
@danb
@Velocio Thought it might be a bit early to tell.
I was under the impression that if using 301 redirects that Google ranking shouldn't suffer.
I ended up building a 5million record dbm mapping file for this exact purpose for one of our customers... who I am sure had been explicitly told by Google that if they correctly used 301 redirects from the old site to the new that their ranking would remain.