Is it better to have one big site or many smaller ones?

determining number of sites

[zyggy]

From an SEO perspective is it better to have one gigantic site (5 million pages) or if it makes sense; 20 sites (250,000 pages each). What effect will it have in search engines.

[dirkji]

From a safety perspective it's better to have many sites. If one domain gets banned you've still got the others.

The downside is the time it takes to promote many domains versus only one.

[cmatcme]

However if you do promote people stand more chance on finding one of your 20 domains than just your only one.

[zyggy]

I am concerned with the number of pages that will be indexed by Google. I have read that its a factor of page rank and was wondering assuming a PR of 7 for the main page and a PR of 5 for the others how many pages would be indexed?
Is there a consensus or estimate for this? Or in a best case scenario where every page is PR 10 is there a limit to the number of indexed pages? If I can acheive a PR of 10 will every page I add be indexed regardless of the quantity - 100K, 250K, 1 million, more?

[andy_boyd]

Don't forget that by building more sites on a single subject or across many different subjects, you minimize risk of damage from algo changes.

[zyggy]

I currently have 70+ sites - I saw the traffic drop across the board on this last update I suspect I may have been penalized for cross links that I used to spread my PR and traffic to other sites, If I had a single large site that would not have happened.

[andy_boyd]

Did you link 'triangularly'?

[zyggy]

All the sites connected to one site that served as a directory site - there were a few sites that linked to other sites(3 or 4) but these were not reciprocal.So there is 70 to one and one to seventy with a few cross links none reciprocal.