My company is currently outsourcing development of 170 WordPress sites and I recently learned that they are developing all 170 in one instance of WordPress. I am not a WordPress expert, but have seen scalability problems with other CMS products in the past where 50 or so sites in one instance experienced major performance issues over time as the site content and traffic grew. As I said, I am far from a WordPress expert, so I thought I would reach out to the community on this one. Is this a potential problem? Or does WordPress scale well when used this way?
It is very possible to scale WordPress to support multiple sites. WordPress.com, for example, has over 13 million. The trick, when it comes to performance, is to: