Keesha had a vma commercial and she didn't perform. She just announced her single at the vmas I think.
Katy will be there and I think she will sing her new song
We don't know if she'll be performing. They've only announced one performance.
There is a 99% chance though - She's recording a commercial for the show, everyone who records commercials for it also perform.
Yeah, that one was slightly different though as it involved the host of the show. In 2008 and 2009 Britney recorded a bunch of commercials with Russell Brand and didn't perform, but when an artist gets a dedicated trailers like Lady Gaga
etc. they practically always perform afterwards. Since Katy's involves Tigers and people being excited over her presence we can assume she has one of these, rather than a Host-related one.
Unless she is the Host, which would be annoying.
The one exception to the rule is that in 2011 Britney got a dedicated trailer and didn't perform, but she got a Special Award and a tribute section dedicated to her. So Katy could be getting that too, I suppose. (She's not.