[objclxt]

From a purely technical perspective, the biggest difference is that the Berkeley team (Snap) re-implemented in JavaScript, and MIT (Scratch 2.0) in Flash. The former also uses XML as a format, the latter JSON (in 2.0).

Like you say, Snap's main difference is it makes some more advanced CS concepts more overt, primarily for use as a teaching tool for older students. To this end, it doesn't have the deep social integration that Scratch does: remixing and sharing are a big part of Scratch.

But that isn't to say that Scratch isn't suitable for high school or college level courses - Harvard's been using Scratch in the first week of it's intro CS class for several years now, with great success. The advantage of Snap is that transitioning from it to pure coding can be less of a leap, due to support for things like recursion, procedures, and continuations.

The Lifelong Kindergarten's remit at MIT means that they tend to place emphasis on a certain age range. In addition to Snap there's also an offshoot of Scratch targeted at very young children (Scratch Jr, which I think is developed by Tufts).

[pjmlp]

So Smalltalk is gone?! :(

[pflats]

Thank you!