I attended a masterclass by Phillip Kawin of the Manhattan School and one of his comments to the student performer was that portato is a "frustrated legato". He's a great guy and an awesome professor. Two of my good friends are now studying with him.
However, if I may put my 2 cents in...

I don't particularly care for the definition of "portato" that is on this thread. I think it gives the wrong impression for pianists of it's nature, technically speaking. These generic music dictionaries are all well and good in most instances, but they don't really meet the needs of the pianist in some cases. For the string player, "non-legato" and "portato" might be similar in the bowings used (I'm not a string player so please correct me if I'm wrong), but for the pianist there are different ways to go about both of these terms, and the technique differs between them.
Non-legato is just what it sounds like. It is disconnected, but can mean that you're not connecting the notes by means of staccato, or by means of portato, or just lifting the fingers off the keys prior to the next note you're playing. Portato is a specific technique that involves disconnecting the notes by means of a wrist motion (not so much fingers here, and not a big wrist motion either) and in my mind at least it involves giving special significance to each note.
When I say that I'm going to play a passage "non-legato", I'm generally saying I will do just that -- make sure it's not legato. I will do this by articulating the passages more clearly. There will be space between the notes, but it is not necessarily staccato.
Portato is a wrist technique.
Is portato a non-legato technique? yes
Is non-legato always portato? no
Is there a blanket term for non-legato (besides "non-legato")? no