Hepcat happened upon this information on Artnet.

The Brooklyn Museum is now offering a new kind of membership through Facebook, Flickr and Twitter. Dubbed 1stfans and priced at a mere $20 per year, the membership category "is a completely new way for visitors to connect not only with the museum but with each other."

The program, which includes special Twitter "tweets" for 1stfan members, began with with a party at a the January Target First Saturday.

Here's the word from Will Cary at the Brooklyn Museum:

What is 1stfans? a 1stfans Membership is an interactive
relationship with the Museum that will happen in the building and
online. We call it a “socially networked” Museum Membership, but what
does that mean? The word has two meanings, which is why we picked it:
it means developing face-to-face relationship with Museum staff and
other Museum Members (literal social networking), and a strong,
exclusive online relationship through social networking sites (you know
them as Facebook, Flickr, and Twitter).

What do 1stfans get? Firstly (pun intended), exclusive events at monthly Target First Saturdays,
where you’ll be able to interact with other 1stfans, Museum staff, and
contemporary artists. Oh, and you can skip the ticket line for movies,
which is pretty sweet. Secondly (no pun there), we will send updates to
1stfans via Facebook, Flickr, or e-newsletter, whichever you prefer.
These will tell you what’s going on at 1stfans events, give you
behind-the-scenes insight from Museum staff, and provide you with links
to other cool stuff going on in the art world. Finally, 1stfans will be
the only ones with access to the Museum’s new Twitter Art Feed,
an extremely awesome way of engaging contemporary artists that Shelley
will describe in greater detail on this blog soon. All of this for a
tax-deductible $20 per-year. Not bad, right?

Who is 1stfans for? You, for one. With 1stfans, people who
enjoy the Museum on-site and online now have an appealing (and did I
mention inexpensive?) way to join the Museum as Members. If you come to
our monthly First Saturdays and want a way to learn more
about the Museum while interacting with Museum staff and making new
friends, then you’ll enjoy 1stfans. If you like the Museum and have an
account on Facebook, Flickr, or Twitter, 1stfans is also for you. Not
only will we keep you updated via those sites, but we’ll also provide
you with cool content and give you a shoutout when you post your own
cool stuff.