Whiteboard Friday - "Supplementary My Dear Watson"

It seems everybody's talking about "Supplemental Hell" these days, what with Forbes reporter Andy Greenberg publishing his extremely lopsided article about Big G's Supplemental Index this week, so we're here to jump on the bandwagon with a little Whiteboard Friday action.

This week, Rand talks about what it means to end-up in Google's Supplemental Index, how you get there, and why it's not necessarily a bad thing.

Also available on YouTube for those that need it.

This week's Whiteboard Friday music is Danger! High Voltage by The Electric Six.

UPDATE: Matt Cutts was kind enough to swing by and clarify a few items about supplemental. Here are his notes:

I'd agree with most of your video and your bullet points, but lean more toward Michael's viewpoint on bullet point #2; duplicate content doesn't make you more likely to have pages in the supplemental index in my experience. It could be a symptom but not a cause, e.g. lots of duplicate content implies lots of pages, and potentially less PageRank for each of those pages. So trying to surface an entire large catalog of pages would mean less PageRank for each page, which could lead to those pages being less likely to be included in our main web index. I'm not aware of an explicit mechanism whereby duplicate content is more likely to be in our supplemental results, but I'm also happy to admit that as supplemental results are different from webspam, I'm not the expert at Google on every aspect of supplemental results.
One fine point to make: when people see the "show duplicate results" link at the end of search results and click it to add "&filter=0" as an extra parameter, the new results you see are not all from the supplemental results. Lemme see if I can find a query to demonstrate that. Ah, here we are, the first one I tried. [site:mattcutts.com foxmarks] returns one result. If I click to see more results, that post has also been indexed at other urls, but at least two of the extra urls are in our main web index, not the supplemental index.

Thanks, Matt - much appreciated!