Agreed, use everything you have available to you.
I'm just saying... We all know some over-achiever lawyer will make hay with it.
As far as the devil in the details goes...
There's a number of Flash videos on the FAA site that are targeted at prepping pilots for ADS-B who all warn it's "not a substitute" for official weather.
Additionally, in my opinion, I seriously doubt the unencrypted non-secured broadcasts of ADS-B would pass even QICP which is required for Internet weather sources to be "official". Although I'm sure the FAA will make an exception for themselves for unencrypted unauthenticated easy to spoof data broadcasts. Haha. (Advisory Circular 00-62)
ADS-B probably won't meet those outage standards for quite a while yet either.
---- QICP sidebar -----
Just noticed that some sites claim XM got the certification but they're no longer listed. Probably due to outages? Here's the list of QICP approved sources.
http://www.faa.gov/about/office_org/headquarters_offices/ato/service_units/operations/qicp/approved/
----- End sidebar -----
AIM 7-1-2 needs an update, badly.
AIM 7-1-3 defines Primary and Secondary weather sources, but good luck finding any weather sources that use that nice simple terminology.
It also "clarifies" that Part 91 operators can use non-QICP Internet sources, but haven't there been cases where our Majesty the Chief Counsel has said Part 91 operators without a record of having a briefing from an official (note: not "Primary" or "Secondary", the already agreed-upon terms in the AIM) source would be considered uninformed?
AIM 7-1-11 gets down to it...
"2. FIS should not serve as the sole source of aviation weather and other operational information. ATC, FSSs and, if applicable, AOCC VHF/HF voice remain as a redundant method of communicating aviation weather, NOTAMs, and other operational information to aircraft in flight. FIS augments these traditional ATC/FSS/AOCC services and, for some products, offers the advantage of being displayed as graphical information. By using FIS for orientation, the usefulness of information received from conventional means may be enhanced. For example, FIS may alert the pilot to specific areas of concern that will more accurately focus requests made to FSS or AOCC for inflight updates or similar queries made to ATC."
RTCA has some GREAT looking documents about the engineering that could be analyzed for significant reasons why or why not a particular service might have engineering limitations or not, and none of those documents are necessarily law or FAA policy. But they're light years aheadof FAA documentation I've found.
They're also $300 a pop so I won't be seeing them any time soon. Would love to read DO-290 and variants. DO-260 looks fun too, but doesn't cover the new 900 MHz stuff. Geek reading material. Mmm. Tasty.