Contagion is an ensemble piece that focuses around one specific thing - a new disease that pops up, which, over time, claims millions of lives, and the fight to stop it. To try and explain how each of the leads (people like Matt Damon, Kate Winslet, Laurence Fishburne, and more) is connected would take longer than I care to give it. Much like Traffic (another of Soderbergh's ensemble pieces), the interconnectivity of the characters can be inconsequential at times, but there's so many of them, trying to explain it would be tedious and confusing.
What's my gripe about Contagion? Well, put simply, a lot happens with nothing really happening. Bad things happen to all of the main players, but they're handled with such distance that it's hard to not just feel like your simply observing something unfolding in front of you, devoid of any emotional connection to the characters. Like The Girlfriend Experience, Contagion comes off almost like a documentary, but it's still a docu directors job to find some way for an audience member to have some sort of emotional connection to the people it's showing, whether positive or negative. In Contagion, I didn't feel either way. It was just a bunch of stuff that happened. I didn't feel fear. There wasn't any "thriller" aspect to the film, as some reviewers have alluded to. As I said before, it just came off as a bunch of stuff that happened.
You're going to kill me for saying this - It's not that it's a bad film, it just never seems to climax at any point. Honestly, I would still give it a B-. I don't know if that's because I look at Soderbergh's work through rose colored glasses, or whether their really is just enough there to have something redeeming happening. I'd like to see it again, see if a second viewing (now that all of the hype has been drained out of me) would fair better, but, it won't be in the theater.
One more quick note - I feel like Soderbergh is getting really lazy with his cinematography, as well. Half of the film looked like it was shot on a 5D. Not to bash 5D's (I shot PHX on one), but when you have a Red Epic at your disposal, and a real budget, don't just jack up your ISO. Light the scene. Shooting in "natural" light above 800 or so starts to really make the image look like crap. I know he's really been into available light shooting, ever since he fell in love with the Red One, but, seriously, you have the resources. Light it.