It increases relevancy: Siloing ensures all topically related content is connected, and this in turn drives up relevancy. For example, linking to each of the individual yoga class pages (e.g. Pilates, Yoga RX, etc) from the “Yoga classes” page helps confirm—to both visitors and Google—these pages are in fact different types of yoga classes. Google can then feel more confident ranking these pages for related terms, as it is clearer the pages are relevant to the search query.
One of the things that can slow-bleed the traffic from your site is the quality (or lack thereof) of the content you publish on your site. Previous Google updates like Panda have already been released specifically to deal with the issue of low-quality content on websites. Long story short: Panda intended to stop sites with bad content from appearing in the search results.
Now, it is not that these sites are not interested in Google users. In fact, they have hired us to help them increase their share. However, they are getting so much traffic from sites like Facebook that it seems there is less urgency about attracting this traffic and less willingness to change the site to meet organic standards. Not long ago, sites would urgently and unquestioningly abide by Google’s standards to court that traffic.