I was curious as to how many posts a single WordPress installation could accommodate before a limit was reached or stability was affected.
So I did some research with my friend Google, and it turns out that the amount of posts that WordPress can handle is determined solely by the hardware that WordPress is installed on, rather than the WordPress software.
WordPress itself is not limited by any post count and can theoretically be loaded with millions of posts. But the server must have the appropriate capacity as far as memory and processing power, in order to filter through all that data without becoming bogged down.
It is comforting to know that WordPress itself is not going to limit the potential size of a blog. WordPress is very lightweight software and it is unlikely that any other blogging software is going to outperform it in this realm.
As the number of posts and pages pile up, WordPress should be able to deal with the load as server capacity is upgraded as needed. There is no need to go in search of a different content management system because of any database capacity restrictions specific to WordPress.