I've added a lot of mods to my phpBB, got rid of the ?sid in the url, removed excessive links etc.etc. but it still doesn't seem to be affecting its rank in the 6 key phrases I want it to, there isn't that much competition for a few of those phrases either!

One thing I noticed is the site has a GPR af 4 on the homepage, static html pages that are linked directly from the homepage have a rank of 3 *but* despite the fact that I have about 4 links on the homepage going to the phpBB forum homepage it still has a PR of 0! wtf! Bad Google!

..actually that reminds me - a lot of the URLs that Google has spidered on my site have ?sids in them!

My best in SEO terms is a PHPBB forum. Was never able to make IPB or VB work from this point of view. I also have some bad SEO-d phpBBBs and myBBs .. in the end I think it's more our fault ...

..well anyway I went ahead and bought vBulletin and vBseo and I swear to god, if anything, my hits have gone down!

Am hoping this is just temporary - after all the work and money I've spent on it! It's only a month since the new forum went live so maybe things will pick up.

Are you using 301 redirects to point the old URLs to the new ones? If not, the decline is most likely a result of all your pages in google's index no longer being valid.

Well I did do some sort of 301 redirect! I can't remember the specifics. However the problem was that there were about a thousand old URLs so I didn't really find any satisfactory explanation on how to do a 'blanket' redirect on all of them...

However if I didn't do the redirect correctly would the hits not have started dropping off instantly? They've really only started dropping off in the last 2 weeks or so, (yesterday I got the princely sum total of 40 organic visits from Google!) before that they were grand, they were at the level they were prior to switching over from phpBB.

> However the problem was that there were about a thousand old URLs so I didn't really find any satisfactory explanation on how to do a 'blanket' redirect on all of them...

If threads have the same ID number with both forum systems, use an .htaccess file to point the old URLs to the new URLs. If threads don't have the same ID number, create a redirectional page at the old URL location which fetches the new ID number of the thread and redirects the user there.

However if I didn't do the redirect correctly would the hits not have started dropping off instantly?

You said it yourself - you have over a thousand URLs in Google's index. Google doesn't re-spider all of these pages every day. Depending upon your PageRank, whether you use Google Sitemaps, and many other factors, expect your homepage to be spidered every few days and other pages (such as forum threads) every few weeks to every few months to even less often, in some cases. When looking at the big picture, you would expect a steady decline over the course of about a month (give or take depending upon many factors). I assume that your homepage has always been accessible. So it would take awhile before Google started respidering old forum threads and finding them broken one after another. It would take even longer before Google came across old forum threads that actually had a high ranking. It might have been that for the first two weeks, the pages Google was respidering weren't getting much traffic but then after two weeks, Google got around to respidering a page that was ranking very well.