brundlefly76 - 8:15 pm on Apr 4, 2008 (gmt 0)

Personally I would expect your average wordpress host to perform fine with up to 100,000 articles at least, I don't see why not. Your only real issue is search speed (and some plugins probably).

However, this is also dependent on your MySQL server chops - MySQL is going to execute the search, not WP.

An easy way to remove search performance issues is with a google site search box in place of wp search box.

Yeah I see no reason not to install supercache as others have mentioned - not only helps with traffic but page delay budget improves as well. Next easy step would be a squid proxy.