Just wondering if there has been any development of having a drag and drop function for matrix. It would be nice to drag and drop things like pdf's and images from my desktop right into the matrix interface and into a folder.
No development is planned for this functionality at this time.
Bummer.
We would also love this feature! Is 'Webdav' the right term for this? Some of the other CMS that we looked at before choosing matrix had this feature.
It is one of the features that's on the "Love to have" list for MySource 4.0, if that helps. 
Yes, webdav is an option that we have looked at in the past.
There is one situation in which you can drag things into Matrix currently. Use the asset map to select "add new image", then in the create screen for the image asset click the "use image editor" button. You can then drag image files from your desktop into the image editor, which will open them. You can then click submit to create the asset.