On March 10 a client's newsroom disappeared out of the SERPS. Any idea why?

[MeritusMedia]

For years the newsroom, which is on the subdomain news.davidlerner.com - has ranked #2 for their brand name search. On march 10 it fell out of the SERPs - it is completely gone.  What happened?  How can I fix this?

[JaneCopland]

Hi Sally,

This could have to do with Google's desire to present the most diverse selection of results for terms, and since there are a range of other websites relevant for the [david lerner] query, Google has dropped the subdomain in favour of keeping the main site in first position, and showing a potentially relevant result for a totally different business in second position (the leggings result). This can happen even when a result has ranked well for years.

To solve this, it would be good if the site displayed "sitelinks" for the brand query (i.e. the six or more links that appear below a branded search, usually linking to other key pages within the website). Obtaining these links usually requires strength and authority that far outweighs other companies with similar names. It's not very common to see subdomains appearing as sitelinks, but it does happen sometimes, when a brand and the subdomain are particularly strong, e.g. https://www.google.co.uk/search?q=ycombinator&oq=ycombinator&aqs=chrome.0.69i59j0l5.1467j0j9&sourceid=chrome&espv=210&es_sm=119&ie=UTF-8 (look at the Hacker News and Y Combinator Posthaven links).

You have a partial duplication issue with both http://news.davidlerner.com/ and http://news.davidlerner.com/news_index.php displaying the snippets for largely the same stories, but this should not be enough to damage the subdomain from a Panda point of view. You may consider restricting bots' access to the /news_index.php page unless it is performing a different task from an SEO perspective for you. Again, I do not believe this has caused the site to drop out of the rankings (and it is still perfectly indexed, ranking for its URL and full name) but it's something to consider tidying up.