In previous versions of Exchange accessing the Directory (or Global Address List) with EWS was limited to just resolving a specific entry or expanding a Distribution list. In Exchange 2013 the concept of the persona's has been introduced http://msdn.microsoft.com/en-us/library/exchange/jj190898%28v=exchg.150%29.aspx . To distill this down a little a persona allows you to have a Contact that can pull its related information from multiple sources while previously everything was just stored in one object in the Exchange Store. There are a number of new EWS operations to go along with personas and the Unified Contact Store the most interesting of these is the FindPeople operation which allows you to do something you couldn't do previously which is enumerate the entire GAL (or any other address list). At this point I should make the point that the GAL is just one of the data sources that FindPeople can search you can also include searching t...
Pushing the Envelope in Messaging and Office 365 Development