Just had a game where Twitch ulted and I put Soraka's E down on him and nothing happened. No silence at all and he wiped the team. How exactly is that fair? Does Soraka's E only silence when it feels like it. Twitch's ult is channeled and he should have broke out of it as soon as I put down my E on top of him but know, he can just stand in it and fire away and kill everyone with no actual skill needed.
Gear Kitty3 votesIt's an activated buff, like Leona or Tristana Q's. Silence just stops him from using any new abilities (and cancels any CHANNELED abilities).
100HorsePower1 votesThat's rubbish because I've seen people use flash in my E.
CrazyBear19871 votesNo need to be mad, it's programed that way, it's not a bug.
But maybe you can complain that your silence didn't stop a flash.
even though it should.
"Flash and Teleport cannot be cast while silenced. This does not hold true for other summoner spells."
EndlessSorcerer3 votesTwitch's ultimate isn't a channel.
Activating the ability modifies his autoattacks and provides bonus AD for the duration of the ability. Silences do not prevent him from autoattacking.
That is why.
dakota saturn1 votesIt's not a channel.......
100HorsePower1 votesBut it should still silence him regardless and stop the ult.
Big Lincoln1 votesno it shouldn't
it's not a channel; it's a buff
CrazyBear19873 votesYour right it DOES silence him, he can't cast any other spell
BUT his ult is not a channel it's a self buff.
Silence doesn't cleanse a target, just stops them from casting current and future spells for a temporary time.
For more clarity, read this: http://leagueoflegends.wikia.com/wiki/Blind#Blind
The Last Ballad3 votesIt does. However, the ult is a one press buff that does not refresh. Twitches R is more comparable to Janna's E or Tristana's Q than MF's R.
Sightless661 votesSilences do not remove buffs. Twitch's ult applies a self-buff. You could prevent him from initially casting the ult with Soraka E, but once he's cast it, there is nothing for a silence to do.
Kyrrion1 votesTo elaborate, it's a self buff Twitch activates for himself.
Neko Caitlyn1 votesHe is not 
He is only auto attacking and silence doesnt stop that
JustMonika131 votesTwitch's ult is a Auto Attack self buff.
Catastrop1 votesIt's an auto attack buff, you can't silence autos.
Eedat1 votesIt does in the sense that he can't activate it if he's silence. If he has already popped it, there is no stopping it. Its not a channel. Silence also doesnt stop similar ults like 
once they've been popped