I review a lot of suggested edits, some of which are attempts to provide wikis and wiki excerpts for tags that don't have them. I tend to think it is very important to have at least a wiki excerpt for each tag to guide people in its use. For this reason, I lean towards approving such a suggested edit, especially when there had been nothing beforehand. However, I sometimes see a suggested edit (mostly for wikis, but occasionally even for excerpts) that are nothing but information that has been copied and pasted from Wikipedia or similar sources (always with quotation marks and proper attribution, of course).
What do we, as a community, think about this? Are quotes from Wikipedia, Wolfram Math World, etc., adequate for tag wikis excerpts? Or for full wikis? Does it make a difference if there was nothing beforehand?