Specifically, the "Janitor Hears Explosion from WTC Basement" in the news ticker includes claims that an explosion occurred in the basement 40 seconds before the first plane impact. Some quick Googling shows that this janitor and another associate went on to try to build a careers on top of these conspiracy theories. One of them even tried to sue President Bush and 155 others over 9/11 with a rambling lawsuit that alleges everything from controlled demolition of the towers to sex trafficking by the defendents.
Not a credible source, to say the least. I have no idea why this site thought to include his claims, but I suspect they're trying to seed doubt about the official timelines.
Cool site, but take some of the editorialized content with a huge grain of salt.