Ranking drop after adding 40,000 new pages

[londrum]

i recently added a new section to my site, which was probably about 40,000 pages, and the very next day i've dropped 30-or-so places in the SERPs.

I've experienced drops like this before when adding loads of new stuff, and it always seems to work itself out in the end, so i'm not worried, but i was just wondering how you would have gone about adding 40,000 new pages overnight, to avoid the penalties.

Would it make sense to noindex everything for a few months, and drip-feed it in more slowly?

I wouldn't categorise it as thin content. Its all database-based (hence the high number of pages), but each page has totally unique photos, maps, travel details, addresses, opening hours, descriptions... There is plenty of unique stuff on each page. They've all got unique titles and meta descriptions too.

[JD_Toims]

I've tried to find the reference a couple of times, but can't -- Way, way back, when GoogleGuy used to post here, he said 5,000 pages a day should be about the upper end of additions and more might raise a red-flag, so I would try to be a bit conservative and keep it there or even lower.

[Simsi]

My initial reaction was that that amount of new pages (assuming they have been indexed already) might dilute the authority rating of other pages on the site. Having never worked with sites of that size, I am not sure what the answer would be but on smaller sites, when I add one or two new pages, I am careful to ensure that the text, navigation and structure clearly explains (to the user) where they fit into the site's food chain.

I aim to ensure that directly related and popular pages or items receive a boost from the new content much more than making sure the new content will attract new visitors, if that makes sense. My view is that that will follow in time from the authority passed up the chain.