PPRUNE, the professional pilots rumour network has a thread going for those interested.
http://www.pprune.org/rumours-news/518568-asiana-flight-crash-san-fransisco.html
Apparently the ILS is not working on 28L nor is there any visual approach slope guidance such as a PAPI or a VASI. This requires pilots to visually judge the glide path, something, in my airline, we are required to demonstrate in the simulator every 6 months or so.
I note that some zealous Asiana employee very quickly tried to spray paint out the Asiana name on the side of the wreckage....
I cannot thank you enough for providing this link - it has provided some excellent insight to the accident. It is important to note that NOTAMs mentioned that the Instrument Landing System and the Precision Approach Path Indicator were both inoperable for Runway 28L. Of course, this doesn't normally present too much of a problem on a good VFR day.
There are things in there talking about the culture of South Korean pilots that I find rather interesting, especially regarding the use of auto-land as often as possible. When you use that automated feature, you tend to forget how to manually land the aircraft by yourself, which is still an important skill to have. Autoland, however, relies on a working ILS system (I know at least this - there may be other things in addition to this, if someone can enlighten me). As mentioned before, Runway 28L's system was not operable.
The description of the final approach of one of the passengers is telling - coming in too high, a steep descent to correct, and then suddenly too low, before the engines rev up. The Flightaware data, although not official, does show that the plane started to climb at about 120 ft/min. This
seems but may not necessarily be, evidence of a poor approach followed by an attempt to go around - that is, give up on the landing and try again.
I'll wait on NTSB, but to me, it looks like this plane crashed thanks to a crew possibly overly used to auto-land, which was taken away from them with inoperable equipment on Runway 28L. This forced a manual landing, which the crew may have been shaky on due to the common use of the autoland, and a bad final approach was flown. The pilots attempted to go around, but didn't have enough time. The plane hit the seawall as the nose pitched up to try to gain altitude. The tail came off on the displaced threshold, forcing the remainder of the plane hard onto the runway, sliding into the median between 28L and 28R.
This is my theory. Not official, and I may be completely wrong. But this is what it looks like to me.