I mean how am I to know what for example yammer does?
IIRC Yammer is like a stun in battles and persuasion in the world (i.e., yammer people to get info out of them).
Yammer, Tractorhold(Democratus), and PAX Stun(Boots) don't do crap and therefore worthless. Don't bother with it in battle. they stun enemies for like 15 seconds.
You should go with Mystech instead.
Another thing I'm sorry for is that Fatimascreen doesn't work for other characters, only Boots. It's too bad, because Grumpos can heal everybody with the Healfield, so I don't get why Boots cannot protect others with FatimaScreen.
Have to admit I don't like how skills and many items lack descriptions.
Items have descriptions down in the status bar when you hover the mouse over them. For example you hover over bracelets like Antiwinky Annulet and in the statusbar down, it says it protects from Winky in battle.