The tipping point came two months later, after a rash of suicides by teenage bullying victims, and a video posted by Khloe Kardashian in which she called Hilton a bully.
In October, the self-proclaimed "Queen of All Media" announced on the DeGeneres show that he would no longer bully celebrities on his website.
"Over the last two weeks I have been doing everything I can to bring awareness to the teen suicides and gay bullying," Hilton told DeGeneres. "In doing so, a lot of people have called me a hypocrite and a bully myself and a big one... From now on I really want to be part of the solution and not part of the problem."
Since then, Hilton has eliminated all the "name calling, doodling inappropriate things on photos and outing celebrities," he told ABCNews.com.
"I have kept up my promise," he said. "I'm still going to have opinions and be critical, but in a fun and sassy way and not nasty and mean-spirited. I haven't really slipped up, either. I'm making an active effort every day to do this and be this way."
The change has not decreased the number of visitors to the site -- nor has it increased them either, Hilton said. But Hilton added he no longer feels a pariah in the gay community. "It's wonderful to be able to go to gay events and speak on MSNBC about marriage equality and not have as many people in my own community be embarrassed or ashamed of me.
Aniston has apparently noticed the change.
"He's kept it up too, which is good," the actress told DeGeneres. "I say good for him and keep it up."
Hilton, who had not planned to go public with the encounter, said he was surprised when Aniston did.
"I'm happy that she did, though," he said. "In that story, others may find hope and inspiration, seeing two people who previously did not really care for each other come to a place of peace and maturity. I wish her only the best and I thank her for the kind words."
Then, he added gleefully, "She even called me lean!"