Google Glossary does not function exactly the same as using the define: operator on Google.
Differences: -related phrases are shown only on the glossary -the glossary is much slower -pagination is only used on the glossary -definitions: different definitions, different ordering of definitions, and different number of definitions. the glossary appears to have *more*
So from all these things it appears that the Glossary is more advanced than the define: operator, although I would have expected it to be the other way round. Possibly the only definition differences are due to a more updated crawl, however it looks more like an updated algorithm too.
Thoughts anyone? I'd like to see the related phrases on Google proper, for one thing. And I'd like to know which is more up to date.