So double the storage of Mega but hosted in the US and they don't publish anything about the so-called security.

The whois record points to Ivan Wong: http://crunchbase.com/person/ivan-wong. The address is the same as the one for his other companies.

> Share what you want with whom you want. Your files are private and we maintain the highest level of security for all your data.

Where can I learn more about this security?

Works well, good deal, nice UI. As far as I can tell your files are -- by default -- exposed to the world if someone can guess the URL.

One annoyance is the url windoid that appears after each upload. If nothing else, it should just disappear when I drag more files into the window (the file drags are received, but the upload dialog won't appear until the dialog is dismissed and a new file dragged in).

This is 2013, not 2003 anymore. Today throwing 100 GB of online storage at people won't cause “yay, I need to claim that and upload everything I have” but “who are these people who want to store 100 GB of my data” and then a dozen questions more about privacy and security. If I don't see any answers easily available, I don't care about your offer.

Is this a file locker or cloud storage service?

The entirely web-based interface suggests the former, in which case the storage limit is curious. Other file locker services have allowed users to upload and share effectively unlimited amounts of files for years.

One of the things I like about Dropbox is that it manages resuming/restarting uploads for me without me having to think about whether I've restarted my computer / my web browser crashed.

In that case, downloading a client is an advantage.

Is it in America?

Free plan has no direct download which is an old trick in the business.

I bet that limit doesn't last for long