You don’t have to design, host and maintain your own extranets. Service providers will let you contract to user their extranet capabilities – also known as e-rooms, but there may be a difference in definitions – and make the step easier to take.
One legal department I know enters into one-year agreements with a provider. Under the terms, the department can quickly set up an e-room, load documents into it, and give passwords to law firms and others for access. When the investigation, discovery effort, or due diligence ends, the department can shut down the online shared-access site and get back its documents burned to a CD. If it is a smaller document repository, the provider will email them back.
The cost depends on such factors as the number of documents, number of users, and length of time the site is open, but my source estimated that each e-room should be less than $100,000. The savings in time, effort and money can be significant (See my post of April 8, 2008: extranets with 13 references; and July 15, 2010: more on extranets with 7 references.).