The main difference between Dropbox and any "web only" hosting solution is that Dropbox replicates the file on all your machines that are sync'd with Dropbox. So the file is both in your hands and replicated in the 'cloud'.
So unless the government pulls their server just as you upload your encrypted file, and somehow your HDD simultaneously fail immediately after upload, Dropbox does not have the same vulnerability as Mega/Rapid/etc-Uploader if you're uploading encrypted files.
There is a caveat though, you are not just uploading, but syncing your local file as well. The governement having your Dropbox file deleted will delete your local file on sync, and you'll be SOL if you didn't keep other backups.
No, if the government pulls the Dropbox servers (my original stated scenario), your client will not be able to communicate with Dropbox servers, ergo your files will stay intact.
If you mean to say that the government will maliciously delete all files WHILE keeping Dropbox servers online. that is a possible scenario, but extremely unlikely as to not even be worth pondering (i.e. there is no benefit to the government to do that).
Though I must also add: Dropbox is a synchronization service, not a backup service. And even if Dropbox was a backup service, you should have multiple redundant copies of critical files. Don't put all your eggs in one basket and all that.
Ahh, good point, exactly (and wow and having no hint of sarcasm as that is blindingly obvious now). Dropbox has this behaviour by default, yes. MacBook Air owners with piddling hard discs (me) may use it as a cloud only store by messing around in prefs, and then forget that it ever worked any other way. I know this misses the main attraction of Dropbox, but one day Ill have a decent disc and will restore it to its former glory.
So unless the government pulls their server just as you upload your encrypted file, and somehow your HDD simultaneously fail immediately after upload, Dropbox does not have the same vulnerability as Mega/Rapid/etc-Uploader if you're uploading encrypted files.