I have not found this to be the case. Imagine a timeshare resort that has one site to sell lodging, vacation rentals, etc. And timeshare is purposely not on the site ANYWHERE. The same company operates a separate real estate site to sell the timeshares (no duplicate content). This month I changed the link FROM the lodging site to include the keywords "timeshare resales location" and now the LODGING site ranks very well for that search term. I changed this after the last major crawl and it was found in the freshness crawls. It may be important to note that the text was alt text of an image link and it was added to every (six) page on the site. The sales website does not reflect any changes as it was after backward links were indexed. However, it may not be that the outgoing link text is being weighed the same. This site has a higher pr than the others and that may be playing a large part as its not a particularly competitive search. Or maybe Google uses semantic spacing to know they are at least related to the timeshare industry. But given that we have tried to keep off any hint of timeshare from this site I can't say that content is important.
MODs if you can't post this I'm sorry as I can't really come up with any other way to say it. They are all very general categories. If not please post (or read anyway) the rest.
GoogleGuy posted somewhere around page 10 of the Sept Update thread (or Google is horrible) about reporting searches that were coming up with less than satisfactory results and what to do. Perhaps if that were a separate thread with GG's name next to it it would be more effective.