I did a search for 'mars bar' while doing some research for a reporter the other day and I noticed that the second result at Google is wikipedia, with a 2nd, indented result about deep fried mars bars (also at wikipedia).
I think this poses interesting questions from a reputation management perspective. The main wikipedia page is not a dreadful result to have appear high up for a company but the indented result is probably not the message that the company would like to project. Especially at a time when all confectionery manufacturers are nervous because of the changing advertising regulations.
Without the main result on wikipedia, the indented result would not rank anywhere significant for this search, and I think it is a little bit of a flaw in the current Google algorithm that it gives quite so much additional weight to other pages on a domain that has one piece of highly relevant content. While it would probably be correct to provide an indented result on the main Mars website about the Mars Bar, I don't think most people who search for 'mars bar' are interested in finding out about deep-fried mars bars!
In general, the domain weighting present in the current Google algorithm causes good results, but on a site like wikipedia, where the relevance of one page is utterly unrelated to that of another, I don't think it is a particularly appropriate result.
##So what could they do about it?
By creating a highly relevant page on the mars.com domain about mars bars (there may be one, but I can't find it), they should be able to get their own indented result for www.mars.com/marsbar (or wherever they put it).
While wikipedia is a very powerful website, a large multi-national company like Mars should be able to manage their reputation significantly better than they currently are - and claim a significant proportion of the first page of results for their primary brand. Doing this would mean that even if wikipedia continued to benefit from an indented result (which I think is unlikely if they pushed it down the rankings, because I don't think the 2nd page is actually that relevant to the search), Mars would own more results above it and hence fewer visitors would see the wikipedia page about deep frying their product.