Disadvantages
Intranet Portals can be a large business cost. The maintenance and management can be time consuming and expensive. Not only is it a cost to keep the portal running but a cost when the system goes offline. Most intranets are established to put all an organization's resources into one place and having that offline can force operations to be put on hold.
Security issues can become an ongoing problem. Unauthorized access is a concern and can have users gain access to sensitive information. Denial of access can cause issues for users needing access for their work.
Having everything in one place is only good if it's organized. Information overload can make finding information very difficult - lowering productivity.
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