For the plane to have landed in the NanMing district of China, it would have had to traverse Laos, VietNam and several hundred miles of China. This simply seems unlikely as the Chinese have stated they have never tracked this flight.

From Sydney Morning Herald
 

"The missing plane is believed to have been involved in a crash in August, 2012, when it damaged the tail of a China Eastern Airlines plane at Shanghai Pudong Airport, according to unconfirmed reports.

....in the incident, the tip of the wing of the Malaysia Air
lines Boeing 777 broke off..."

Malaysia Airlines plane missing with more than 200 passengers on board

Correction:: Took off at 12:41; Lost contact at 2:40

Not sure why people are referring to Flight Aware... Flight Radar24 had the aircraft last position about halfway between the coast of Malaysia and the coast of Vietnam. Interestingly, following and preceding aircraft at the same route and level are in full coverage.

The airways from KL towards Beijing don't cross over Laos or Vietnam, they are mainly coastal routes that pass initially to the south of Vietnam, in the area of Con Son Island, and on up the coast towards the area of Guangzhou to connect to the airway up to Beijing. So, if they lost contact about 2hrs into the flight they would have been over water, albeit there does seem to be some confusion as to just when LOC occurred. If they went into the water, this would of course hamper any SAR response and could account for the lack of an ELT signal. Weather seems relatively benign, as it is this time of year, and of course, if it had landed anywhere, which it would have done by now, we would have heard. Also assuming no last minute contact with any ATC unit, I think it is sadly safe to assume that an immediate and non survivable incident has happened. :(

FR24 have just tweeted that they have good coverage in that area, with planes in contact all around where they 'should' have been. However ATC contact is not lost for another 1hr 20mins.

So either are something happened to the transponder at 17:20UTC which was part of a chain of events leading to loss of contact 1hr 40mins later OR this is unrelated transponder issue either onboard or with the ADS system FR use.

During the hours after the LAM Embraer flight was missing some rumours on Twitter said the aircraft landed safely.
I do not know the reputation on this source but i have my doubts. Atc should have been able to monitor the aircraft.

Chinese TV news still has the plane missing.

Still unconfirmed, anyway:

Missing plane found safe. Cockpit comms malfunctioned | FZ : Malaysia News - General, Political, National, Business, World

PETALING JAYA (March 8): The missing Malaysia Airlines Boeing 777-200 has landed safely in China.

fz.com was informed by a source at the Emergency Response Team that the Beijing bound MH370 piloted by Capt Zahari Ahmad Shah had landed this morning at Nanming, Guazhou.

It had lost contact with the control tower at 2.40am, after taking off from Kuala Lumpur International Airport (KLIA) at 12.35am.

According to sources the plane’s transponder (cockpit communications system) had malfunctioned while over Vietnam airspace, causing the loss of communications.

At the two hour + mark, they would have been abeam VVTS or a bit north talking to HCM control. The route runs up to the coast past Hainan then they would crossed into China through VHHH.

If they were safely in the ground we'd know by now.

Come on people - think about it - a 777 landing at even a remote airfield - no radio messages, not one person having a working phone....

Sorry, It's Gone
 

Use FlightRadar24 and playback starting at about 17:15 UTC. MAS370 is the one sorta midway between Malaysia and the closest part of Vietnam. Its at 35,000 on heading 25 until 17:19 (01:19 local), then it goes to zero feet. Radar coverage is good in the area.

Where the plane is (generally) is not the question. What caused it to get there is the question. Sorry. That plane is not on the ground anywhere.

Also, airlines don't call next of kin if they think there's any hope.

Chinese state television reported that 160 Chinese nationals were onboard the flight.

One Russian citizen was among the passengers, ITAR-TASS news agency reported.
Also an unknown number of Australian citizen.
In total 13 nationalities were on board the flight.

It does seem extraordinary to me that Air Asia CEO Tony Fernandes referenced the "radio failure & safe landing in China" rumour on his twitter account. That seems very rash, IMHO. Beyond credulity to see how that can be true, sadly.

Exactly. Some very irresponsible comments and reporting going on in social media. It is looking very grim however.

Pressconference delayed. Will start at top of hour.
MAS denied rumours of aircraft landing in China.

There is already a Wikipedia entry for MH370. It reports registration as 9M-MRO, delivered in 2002.

Malaysia Airlines VP tells CNN no distress call or problems reported from MH370 before disappearance, plane was at 35K ft

So a catastrophic event over water, with no time or ability to communicate, is what that may imply. Ominous.