The number-one thing Disqus had going for it was Daniel Ha's omnipresence and superhuman kindness. When they had a forum, Daniel Ha made an effort to answer every question, no matter how ridiculous or rude, in the most elaborate, inhumanly kind way. If a blogger - oftentimes a big one - mentioned Disqus but expressed some reservations, Daniel would be quick to contact them with offers for a complete transition walkthrough - and I am sure a lot of people took him up on the offer.
Second, you can not whisper Disqus's name in a toilet stall in the outskirts of Siberia without Gianii or Daniel hearing you. They've got all kinds of alerts configured so they can respond to every publicly declared frustration with Disqus, and they're impeccable at what they do.
Daniel Ha's effort to fight any reservations and unfounded doubts about the service is a case study that should be in every entrepreneur's mandatory curriculum. I think of his philosophy every time I consider the community aspects of a hypothetical project.