Responding to a number of comments from various people below...
From: Shawn Barrett
The way I understand it, trademarks are intended to help sell actual real life PHYSICAL PRODUCTS (or services). If someone sets up a diner called Denny's that is modeled after the real life restaurant, and sells virtual food there along with virtual Coca-Cola and displays posters of the Cuervo logo, are they really violating any laws in real life?
In some cases, even if you were not technically infringing their actual trademark, you would be violating their rights in that you “passing off”your goods and services as their's and “diluting” their mark by using it in a way that an average consumer could be confused into thinking that your SL business was owned by Denny's, Coca-Cola, or Cuervo. However, as a practical matter most famous brands like the ones you have mentioned will have registered their trademarks in IC 042 for “online computer services” or something similar--that would cover use of the mark in SL.
No--she's not. Furthermore, ownership of a domain name and ownership of a trademark are NOT the same thing. You can easily own one without owning the other. While it is possible to gain possession of a domain name, that you have a registered trademark for, under ICAAN Uniform Dispute Resolution or under the US Anticybersquatting Consumer Protection Act, it is not always a sure thing.
From: Candace at the Moon
Recently, someone tried to challenge our use of Amy Brown FaeryWear by Gypsy Moon and Amy`s lawyer made sure we have solid ownership of the name.
Amy needs to demand her money back. Other than some common law rights, you own nothing.
Her lawyers submitted an application on 25-Mar-2005, the USPTO responded with an office action refusing registration because there was a Likelihood of Confusion between the the proposed mark “Amy Brown FaeryWear by Gypsy Moon” and an existing mark “Faerie Wear” (No. 2775434), which was awarded for similar goods and services. There were also a few less other issues, including a need for more specific identification of the goods and services and a requirement that the “Amy Brown” portion of the proposed mark be supported by a statement from Amy Brown authorizing the use of her name.
The USPTO gives you six months to respond to an office action on a proposed mark. However, Amy Brown's lawyers did not, and on 22-May-2006, the USPTO mailed out a Notice of Abandonment, ending the application for non-response. The abandonment is a bit puzzling, as the USPTO's objections could have been addressed easily by changing the mark to something like “Gypsy Moon by Amy Brown”, submitting a statement from Amy Brown, and elaborating on the goods and services. It would have been a fairly simple to do.
As it stands, it's too late even for Amy Brown to file a petition to revive the application, as more than two months have passed since the date of the notice of abandonment.
From: katykiwi Moonflower
On a more serious note, I have proposed a feature that would allow all premium members to select one business name via a Linden maintained database. and that name would appear in the members profile. No other member would be permitted to use that name while it is registered to another member.
As I said upthread, I think this would only end up giving SL businesses a false sense of security. Since a US federal registration would trump any in-game registry, a SL Business Name Registry would provide little real protection from outside game businesses using the same mar (or applying to). Though for the limited purposes of keeping two businesses--in the SL virtual space--from using the same mark, it would work, LL would need to be clear that such a registry would provide little protection from RL trademark holders.
From: katykiwi Moonflower
You must actively defend against all infringement on the use of that trade name, in whatever part of the US it occurs, or you lose your rights to it. The name is considered abandoned, which is exactly how the name Gypsy Moon became available.
Just a nit--the application for “Amy Brown FaeryWear by Gypsy Moon” was abandoned for failure to respond, not for failure to enforce. Generally the USPTO will not list a mark or application as “abandoned” because it has become generic. That's usually the determination of a court. “Abandoned” in the USPTO database usually means that a mark has not been renewed or an application has not been responded to.
From: katykiwi Moonflower
Registration can take up to 18 months. During that time you may use the letters (tm) to indicate that you have claimed legal usage and during that time the trade name will not appear in the US patent office database records.
Another two nitpicks. 1) The registration process can take far longer than 18 months--especially if you have to respond to numerous USPTO office actions, go before the Trademark Trial and Appeals Board, or someone raises objections when your mark is published for opposition. Eighteen months is closer to the minimum time to get a mark in my experience

2) Anyone can use the “TM” or “SM” symbols--whether they have applied for a registration or not. They simply indicate that you are claiming ownership of a mark. It's not analogous to use of a “Patent Pending” (which you may only use after filing at least a preliminary patent application).
From: katykiwi Moonflower
You will not have registered trademark protection until the 18 month registration process is completed.
True--but if someone else applies after you do, you have priority based on your application date, rather than the date the registration was granted. For example, should Amy Brown now reapply for a “Gypsy Moon” mark, your pending application (assuming it is a US federal registration application) would have priority, even if hers wound its way thought the registration process first.
From: Lost Newcomb
Regardless, she (real GM owners) sounds much more stable in her claim for the trademark. And I do like your BS. You implied owning that company twice in this very thread, and it does not take someone 2 mins to inquire if you indeed do own it.
No--the RL “Gypsy Moon” people are not in good shape here. Their best bet to keep any rights to the name (without going to court) would be to carefully watch the USPTO's publications for opposition, and file a formal opposition when katykiwi's mark is published. And the success of such an opposition would be far from a sure thing. I'm guessing--but do not know for sure--that Amy Brown's non-response and abandonment of her previous application would be held against her there.
From: Jesse Malthus
Notice that the wordmark in question is "AMY BROWN FAERYWEAR BY GYPSY MOON", not just "GYPSY MOON." As you don't own the trademark yet, and it's not expired, it's still fair game to use it.
The proposed mark for “Amy Brown FaeryWear by Gypsy Moon” has not expired because it was never awarded in the first place! And as I mentioned earlier, katykiwi's pending application now has priority over Amy Brown's abandoned application.