Hands On
When you click on the setup (gears) icon above or go to the IP address of the NSA325 and log in as admin, you land at the page below. This landing page is also the status page and you can see that it chock full of information. Arranged vertically along the left side of the screen, you'll find major groupings of features in an expandable/collapsible tree. Many of the features are common to virtually all NASes products, so I'll just highlight a few that I think are noteworthy on the NSA325.

NSA 325 Administrative home page
Network > Telnet
By enabling Telnet, you have root access to the NSA325 using the admin password. No hacking required!
Applications
• FTP – you can enable FTP an separately enable/disable anonymous FTP access. You can also individually set a maximum upload and download rate.
• Media Server – if you enable the Media server, you have access to the Twonky Media Server console on http://NAS_ipaddress:9001. The NSA325 is currently running TwonkyServer Premium version 7.0.9
• Broadcatchting – you can have the NSA325 automatically download frequently updated items like podcasts and RSS feeds
• Copy/Sync – this menu lets you select the volume on the NAS to be used for either copying or syncing with an external USB device. Press and release the button on the front panel to copy. Press and hold the button until you hear a beep to synchronize.
• Package – This is one of the best features of the NSA325. It lets you customize your NAS with additional features and functions by installing packages from the ZyXEL. Click "Retrieve List" from Internet to get the latest available packages. Not shown on the screenshot below are: SqueezeCenter (for Logitech's Squeezebox); Syslog; Tftp support (on port 69); WordPress; eMule (P2P file sharing) and pyLoad.
Packages add additional features to your NSA325
Auto Upload > Flickr/YouTube
Here you can create “watch folders” on the NSA325 that are automatically uploaded to either Flickr or YouTube.

The NSA325 can automatically upload files to Flickr, YouTube or FTP sites
Time Machine
Mac users will appreciate that the NSA325 can be used as a Time Machine Target. I successfully configured my Mac (Lion 10.7.5) to use the NSA and created the initial full image of my Mac.
The NSA325 can be configured as a Time Machine target
Sharing > Users/Groups/Shares
These three menus let you create users and groups and then assign privileges to top level shares using those groups and users. Private shares are not automatically created when you create a user – you have to create private shares, if desired, in the Shares menu. The Shares menu also lets you enable/disable a share, enable a recycle bin, or publish a share to the Media Server. There are no user or group quotas. There are predefined shares for video, photo and music as well as a built-in public share and a built-in private share for admin.

You can assign user or group rights for each share
Maintenance > SSL
In addition to the standard maintenance items of logs, firmware updates, saving configuration, the NSA325 lets you easily install a downloaded certificate, edit a self-signed certificate, or create a certificate to be authorized by your own Certificate Authority. You must do this if you want to enable HTTPS access to the web admin or to enable secure FTP.
Protect > Backup/Restore
These menus let you create one or more backup jobs to backup (full or incremental) or synchronize shares, files or folders to another NSA NAS, onto a different target on the same NSA325, or to an attached external USB drive. Note that network backup to a standard rsync server is not supported. Like Buffalo, ZyXEL has elected to allow network backup only to another of its own NASes.