Developer forum

On the apps using lucene you can track queries.

TrackQueries is a setting on the Product Catalog (and the underlying Query Publisher module) that, when true, logs each executed index query — including the free-text search term and result count — into Dynamicweb's Tracking subsystem so it can be analyzed later. It requires that tracking is enabled.

When enabled, it builds EventData records:

• One Indexing.Query event — EntityType="Query", key = query name (the .query file path), sub-key/query string = the request querystring (this is where the free-text search term lands, since the search box value is a request parameter), Value = result count.
• One Indexing.Query.Parameter event per query parameter (EntityType="QueryParameter"), one per value for multi-valued parameters.

These are passed to Tracker.Current.TrackEvent(...), and if there's a page view it also tracks a view.

4. Where the data gets stored adds the events to the tracking context; on request execution they're flushed via the repository to a SQL table named TrackingEvent Relevant columns:

But there is currently no report. You can do
SELECT TOP 10
    TrackingEventEntitySubKey   AS SearchTerm,
    COUNT(*)                    AS ZeroResultSearches
FROM [TrackingEvent]
WHERE TrackingEventName       = 'Indexing.Query.Parameter'
  AND TrackingEventEntityKey  = 'q'
  AND TrackingEventValue      = 0
GROUP BY TrackingEventEntitySubKey
ORDER BY ZeroResultSearches DESC;