Not to say it's flawless to retrieve information (and personally I would like to see an archival-type client / tempted to make one), but it would be wrong to say it doesn't exist! :)
The Mac client has a search button and it asks me for a search term. When I enter a string (which I know to appear in the room I selected) the search reports ""No results" ... I'm not sure if I'd call this an "existing search capability" either ;-0
OK, I have to admit that the latest Mac client now (finally) has an export feature, as I just checked. So it seems usability improvements happen, albeit slowly and unevenly deployed.