Forum:"When this card is summoned"

Hey everyone, my first time posting here. Hope to get a few awnsers for a bunch questions I have.

There are multiple cards with "When this card is normal summoned", or "When this card is special summoned-", however I've noticed a few cards that just say "When a monster is summoned". An example of this would be Torrential Tribute: "Activate only when a monster is Summoned. Destroy all monsters on the field". Does this effect count for all types of summoning, or is "summoned" just short for a normal summon? Can I activate this card on special summon like Monster Reborn?

My second question would be about the following effect (Dark Necrofear): "This card cannot be Normal Summoned or Set. This card can only be Special Summoned by removing from play 3 Fiend-Type monsters in your Graveyard." I found this effect to be a bit confusing. Does this mean that I can special summon this card to the field just by removing 3 fiends from my graveyard? Or does it mean that I have to use a special summon effect (something that allows me to special summon something from my hand or deck), and then remove 3 fiends from my graveyard, to make the special summoning effect possible? Third question adds really well to the previous one: Since this is a special summon, can I use this during the same turn I do a normal summon?

I can remember being confused about more things, but these are the ones I remember at the moment. Wouldn't want to flood a thread with too many questions. Thanks in advance for any help, I'd really appreciate it. :)