Selected answers from the Dumb SEO Questions Facebook & G+ community.
Lyndon NA: Short:It`s not likely to make any difference - there should be no negative to using the punctationLong:It depends on context.In most normal cases, punctuation is typically ignored.But if the punctuation is "significant" (it`s actually part of the term), then those that search for the term with the punctuation will likely see results with the punctuation more than those without.