On 8 Nov 2013, Timothy Pearson verbalised:
$HOME/.nfs* $HOME/.DCOP*
[...]
The .nfs files are NFS lock files.
The .nfs files are NFS 'silly-delete' files. In Unixlike operating systems, it is expected behaviour that you can delete a file you have open and continue using it -- but an NFS server, being stateless, has no idea what files its clients have open. So as a hack around this, when an NFS client gets asked to delete a file it has open, it requests that the server rename it to .nfs{random junk} instead, then sends a delete for that when it is closed. This is a hack and clearly cannot work in all cases (i.e. a process on one client holds a file open, and a process on another client deletes it) -- but in practice it works well enough to be getting on with, except if the client crashes. Then it cannot ever send the delete request for the silly-delete files, and they build up.
Because they are the wreckage of old files (often temporary files) that were deleted but not closed, it is normal for them to contain actual, real, useful data.