Yes. IQueryable actually implements an expression tree, which means that it may never be executed, at least directly. LINQ to Entities (Entity Framework) actually evaluates the expression tree to build SQL statements, then runs those and returns the results (after coercion back to the mapped POCO object).
Right. Actually Linq to SQL did the same thing, but a big philosophical difference is Entity will reject stuff that it can't resolve from the database instead of just letting you do whatever (which may involve multiple queries).
