Seems she had no idea what she was in for. Must have been a bit of a shock.

Tony Hinchcliffe, who wrote jokes for Coulter to recite at the show. In Hinchcliffe’s telling, Coulter had no idea of what went down at the somewhat iconic roasts, and refused to learn. “We asked her if she’d seen a Comedy Central Roast, and she said no,” he said. “She had no idea what was going to happen going into it.”
http://www.spin.com/2016/09/ann-coulter-was-at-the-roast-of-rob-lowe-because-she-didnt-know-what-a-roast-was/

That was brutal.

deserved...

my god jeffrey ross is turning into something fat old and huge.

Usually I just want to slap Ann Coulter.

This made me cringe, and then want to slap Ann Coulter.
Then cringe again, then want to slap Ann Coulter.
Then the cringing...

This went on for 1:56.
Now I just want to slap Ann Coulter.

I don't know if this was more brutal than the usual roast. I saw the headlines back when it aired and finally got around to watching it here, but it didn't seem that much worse than usual. She had to expect people would insult her too, as her set included insults to others on the dais, so it shouldn't have come as a shock to her that she'd have insults her way too. Her set bombed for lack of comedic timing, comedy is hard (as Edmund Gwenn said, and later attributed to Jack Lemmon among others... http://quoteinvestigator.com/2010/10/26/comedy-is-hard/ ).

I have seen Coulter enough times on Bill Maher's show to know nothing fazes her.
She will just take any insults without batting an eye, on the basis of a false sense of superiority, and a correct sense that her media appearances are mostly just to sell books.
She also enjoys playing the villain (the 'heel' in wrestling terms).

Here is the full roast. https://youtu.be/1cb9kIlKAUI

I now got curious and watched the Roast waiting on my PVR (it's not a good one).
But. Oh. My. Word. Did Ann Coulter (who by the way was quite open about her book promotions, audience didn't appreciate that openness) bomb or what. The answer: she bombed.
Like bad. Like worse than 'The Situation' (yes, I watch all these CC roasts, I am not proud of it)! Like a lot worse, at least the situation tried without success to get out of the hole on stage.

Here is her performance in a low-talking video that will probably be taken down before I submit my comment:
https://www.youtube.com/watch?v=XCyRRpojn7I
Here she is saying she did great and it's all the fault of bad editing:
https://www.youtube.com/watch?v=T5Jsl1OFjtU
Here is the writer saying it was not his fault, but I don't really believe that is true, the delivery is terrible but the jokes were also sh*t, and I don't believe for a second she wrote that material herself as he claims, because the material is exactly in line with what those CC roast speeches are:
https://www.youtube.com/watch?v=6FtO15N0iho

Supposedly he yoyos. Gets in shape to tour, then goes total coach potato in between. Obviously this appearance was during a non-tour time.