I work for an Indian OTA based out of Bangalore. We have a travel planning product called Small World (www.cleartrip.com/smallworld) that aggregates content from a number of Free sources in addition to some proprietary sources we have tied up with. The travel content content includes descriptive guides such as: http://www.cleartrip.com/smallworld/new_york/4fcd2082e44d78692f187dc9/guide We fetched all our guide content from Wikivoyage (completely moved over from WT a while back). As per our understanding of the attribution requirements, we have inserted the following text "The above text is available under the Creative Commons Attribution-ShareAlike 3.0 license from Wikivoyage. A list of contributors is available at the original article on Wikivoyage." with the links to WV article and the full list of contributors - which I see also include the original WT authors for old articles.

We recently received an email from WT's legal team telling us that the license requires us to attribute WT. The letter goes on to say:  "In view of the foregoing, Internet Brands, Inc. hereby demands you cease and desist copying content from Wikitravel.org, unless you provide proper attribution to wikitravel.org as the original content creator."