Wolfram|Alpha does take boolean, but in the notation that Mathematica likes (&&, ||, !, etc). You can also write it out in plain english (NOT A OR B, etc).
I used it to simplify some kmaps for class the other day and it's very nice: prints out a truth table and various types of minimal forms.
"Conventional" boolean operators work as well. Again, I suspect that it depends on whether a developer has mapped something ToExpression can consume, either via forms, boxes, or unlocking the function itself. (This would be consistent with the "throw more mud at it" comment.)
As a Mathematica and WApro user, I find most of the utility in not having to import random datasets myself. As every researcher, I have a disgusting library of scripts that often involve curl, groovy, awk, sed, etc., to pull info into mma. It's nice when that becomes SEP[1].
I used it to simplify some kmaps for class the other day and it's very nice: prints out a truth table and various types of minimal forms.