Have to try this one out! According to the Developer Wiki at http://wiki.developers.facebook.com/index.php/Fql.multiquery:
This method takes a JSON-encoded dictionary called queries where the individual queries use the exact same syntax as a query made with fql.query. However, this method allows for more complex queries to be made. You can fetch data from one query and use it in another query within the same call. The WHERE clause is optional in the latter query, since it references data that’s already been fetched. To reference the results of one query in another query within the same call, specify its name in the FROM clause, preceded by #.
For example, say you want to get some data about a user attending an event. Normally, you’d have to perform two queries in a row, waiting for the results of the first query before running the second query, since the second query depends on data from the first one. But with fql.multiquery, you can run them at the same time, and get all the results you need, giving you better performance than running a series of fql.query calls.
