Integration
Plone is open and pluggable: many products and application work well with Plone, both in the open source and the commercial software world.
Web servers, databases, authentication systems:
It is a common choice in production environment to make Plone / Zope run with Apache as a web server.
Proxy servers can be also used to speed up a Zope / Plone site; the Squid Web-proxy cache, for example, supports purging and load balancing and can be used in front of Zope or in the Plone / Zope / Apache configurations.
You can decide to use, or keep on using, your LDAP or Active Directory server with Plone, to autenticate users on a Plone site;
distributed authentication can be run on Plone sites with OpenID and single-sign on features will be avaiable by default in Plone3
Plone can be configured to start running a WebDAV server, so that Plone content can be accessed via WebDAV, and also send/receive content via FTP, if it is needed.
Plone uses by default the Zope Object DataBase but this is not an obstacle to integration with relational databases: you can use Archetype tools to write SQL statements and store/access data in databases different than the ZODB.
"A CMS brings a world of opportunities to
apply rich behavior to data "
More tools:
Specific products are often developed to accomplish different needs. Just a few example:
Analytics for Plone provides a Google - specific Search Engine Optimization tool (Quintagroup);
Plone Desktop provides a deep integration with desktop applications and enhances Windows(tm) desktops to work with Plone CMS (Enfold Systems);
Dump-On-Cd allows to replicate a populated site on a cd for offline consultation.