Traffic drop 50% after migrate phpbb to vbulletin

I have a forum with considerable size (over 1.5 million posts). It ranked well at Google and Yahoo.

After hearing many good things about VBulletin from people here and elsewhere, I went ahead to purchase and install VBulletin (3.8.2 )with VBSeo to my site, replacing the old phpbb forum. I have taken into considerations previously indexed pages (340k pages from Google) , and made 301 redirect to the appropriate new URL. Eventhough not perfect, I manage to redirect at least 95% of my traffic to the new URL.

Problem is, search engines seems to have problems assigning ranking to the new URLs. The indexed pages drops daily, now 280k pages at Google. The traffic drop even worse. From previously average 12k visitors a day, now I only get 5k a day. Needless to say, my AdSense earnings suffers a massive drop, now with only a little more than one third from previous earnings.

Hope things can turn around, if not I think I'll have to migrate back to phpbb.

:sigh

Hi Alfan,

You're in the rough period now. Moving from phpBB to vBulletin is a major move. Fortunately, vBSEO is going to help with the transition, to accelerate it. Do you also have our sitemap installed?

Are you including your showpost pages? Since you have such a large content database, the re-crawling would be far more effective if these were eliminated. However, before you would make that decision you would want to confirm where or not you were getting traffic to those pages before.
Do your ShowPost Pages Get Search Hits? - vBulletin SEO Forums

I would also recommend that you seize this opportunity to do a critique request. Since the re-indexing process is ongoing, this is a great time to also implement other tips that might help your forum improve.

How long ago did you do the move? What were your long tail stats for the same # of days (a) before and (b) after the migration?
What is the Search Long Tail? - vBulletin SEO Forums

2 months on after I migrate from phpbb to vbulletin.
Traffic from Google seems to be somewhat stabilized.
However, Yahoo traffic is still in the free-fall mode.
When I first migrated, Yahoo drop is the least significant compared with Direct traffic and Google traffic.
But now, it has the highest difference compare with before migration.
Worse, it is still dropping everyday.
See the attachment

and here is what happen my top 5 keywords after migration

Good to hear something positive. Thanks

This Yahoo things hurts a lot, since visitors that Yahoo sends are most likely to have low bounce rate, high pageview per visit, and high adsense clicks.

Please be sure to submit a critique request if you have not done so yet. I believe in 6 months time, you should be able to blow away your starting stats.

As this is a fairly common migration would it be too hard to write a set of .htaccess rewrite (r=301) rules to pass all incoming requests off to the right scripts in vbulletin?

I'd say the dead pages is where you lost most of your pagerank/juice/rankings what ever you want to call it.

If anyone ends up writing the rules please get in touch with me!! If I do we'll write post them on one of the vb forums.