In the spirit of sharing content, the Creative Commons Attribution-ShareAlike 3.0 Unported License shall apply to all pages (existing and future) at visitusers.org.
In a typical web site where articles are "published" once by a single author, it is easy to know the copyright status of those articles. Articles at visitusers.org were contributed over many years by many members of the VisIt community with the intent that their content would remain available to the community. No specific licensing policy was outlined for this site at its inception, though the intent was and is for free reuse. A wiki is a complicated thing because individual pages created by a single author may evolve over time to include content by several contributors. The expectation here is that content is made freely available.
That is not to say you have no obligations to the visitusers.org site or to the content authors if you harvest content from this site. In a typical web setting, copying someone's content is covered by copyright laws and is frowned upon in general. In that setting, one should seek permission to copy content lest the originator lose their idea or web traffic as a result. It is more polite to link to content. A wiki is a broad collection of content created by many so there is no one user in most cases who could approve copying and we should allow it anyway. Nevertheless, deciding to take significant parts of the wiki for whatever purpose, may have a detrimental effect on visitusers.org and should be reconsidered. Visitusers.org is a good site with a good track record and deserves to be maintained and improved.