From: Sabrina Blabbermouth
I have to ask is Linden Labs FDIC insured? [...] The reason is this. Residents pour US$ into SL each day. LL then uses those US$ for operating expenses, salaries, maintenance, etc.
What you are describing is a business; not a bank. Customers pay the business money for a service, and the business uses that money to meet expenses and expand or make a profit. That's in no way a banking institution.
From: Sabrina Blabbermouth
Then when things like this happen (Auction Exploit) and the threats to legally attack LL, I would have to imagine that some people rush right over to the Sell Lindens page and/or request a payout ASAP! (I would/did).
Hope you didn't take a bath on your L$; those legal threats against LL are laughable. No court is going to issue an injunction that would shut down LL for the reasons stated in that post. The very fact that the poster made such a threat is evidence that he has a very poor understanding of the law.
From: Sabrina Blabbermouth
So if this were to happen all at once, and several hundred individuals requested a payout amounting to more cash than LL had on hand allotted for payouts, we wouldn't get paid.
Not only that, but if a court battle arose and LL had to pay legal fees, and for some reason wound up losing assets and/or funds as a result of this, then what would happen to the money that we have invested in LL?
LL is not a bank. It would be foolish to keep more than a month or two worth of tier in a US$ balance in your account with LL. The only money that it makes economic sense to keep there is money that you are going to use to pay LL.
However, for all practical purposes, LL is going to be able to pay you--unless they were to go bankrupt. Then the same thing that would happen that would when any business that has money on account becomes insolvent. You would become an unsecured creditor.
LL might go bankrupt someday. It is, after all, a VC-funded internet company. That's a risk. However, if it ever does go under, it won't be because of the frivolous lawsuit threatened in the links you listed.
From: Sabrina Blabbermouth
Are they FDIC insured? It seems as they classify as a financial institution being that they trade and hold US$. Not much different from PayPal.
PayPal is not a bank and is not FDIC insured, either. From the PayPal ToS:
From: PayPal ToS
If you do carry a U.S. Dollar balance in your PayPal account and do not enroll in the PayPal Money Market Fund, PayPal will pool your funds together with funds from other Users, and will place those funds in accounts at one or more FDIC-insured banks ("Pooled Accounts"

. Those funds may be eligible for FDIC pass-through insurance. Any balances that you hold in currencies other than U.S. Dollars will also be pooled and placed in bank accounts on your behalf, but will not be eligible for FDIC insurance.
From: Sabrina Blabbermouth
The fact that LL has created its' own currency does not make it any different. It's still US$ in the end.
It makes a difference because you have agreed that it does when you accepted the Second Life Terms of Service. From the SL ToS:
From: SL ToS
6.4 Second Life Currency. You acknowledge that the Second Life service presently includes a component of in-world fictional currency ("Currency" or "Linden Dollars" or "L$"

. You agree that Linden has the absolute right to manage, regulate, control, modify and/or eliminate such Currency as it sees fit in its sole discretion, and that Linden will have no liability to you based on its exercise of such right.
From: Sabrina Blabbermouth
I enjoy this game as much as anyone, don't get me wrong. But before I go buying and island...or 100 islands...I would want to be sure that if something happens and my 180,000 USD is stuck in my account...that I would be able to get my dough out!
Trust me; no one with 180,000US$ is going to leave it sitting in an only semi-liquid, non-interest bearing, uninsured LL account.