In 2009 I added the Steampunk subcategory. Steampunk in and of itself isn't goth, but a lot of goths are interested in it, and there's a lot of crossovers between the genres. Steampunk doesn't have to be dark though. Anyway, not knowing much about steampunk before I dove in, I found it quite interesting and challenging to explore the online steampunk community and its wealth of resources.
1. Brass Goggles
This blog and its related forum is the epicenter of the online steampunk scene. They focus on "the lighter side of steampunk," and ask that posts with partial nudity be clearly marked as NSFW (not safe for work). The forums are nicely categorized into different sections for costuming, writing/literature, food and drink, music/film/TV and games, propmaking/crafts, etc. You could really get sucked into spending lots of time here every day if you weren't careful!
2. Steampunk Empire
A well-organized Ning social network. The forums include Literature & Language; Film; Food & Libation; Music; Fashion; Events; Games; Marketplace; and Maker. There are also several Groups, including The Steampunk Star Wars Society; The Aether Guild of Writers; Bay Area Steampunk Society; French Steampunk; and The Imagineer Guild.
3. Clockwork Cabaret
A weekly radio show. It's on the air on Mondays in Chapel Hill/Carrboro, NC, but you can also listen to it online.
While there are many great steampunk conventions (including Steamcon right here in Seattle), the website design here is so good at transporting you into the theme, I wanted to mention this one. November 5-7, 2010, in Madison, Wisconsin.
5. Steampunk Workshop
"Serving the backyard industrialist since aught six." A blog with Steampunk projects including a cool Victorian steampunk style computer and keyboard. Recently posting about the US Steam Land Speed Record Attempt, artwork by the artwork of James Ng, and open source jewelry.
6. The Steampunk Librarian
A steampunk news blog. A good way to quickly check up on what's going on in the community.
A website chronicling "sepiachord" music - influenced by steampunk, Neo-Victorians, etc. "SepiaChord hosts a lifestyle for a past that never was, and for a future that never will be." Reviews, info on upcoming events, and news.
Richard Nagy's website showcasing technical art and steampunk contraptions, including the infamous steampunk laptop. He's currently working on some really cool keyboards.
9. Steampunk Lolita
I love crossovers, and I'm delighted to see the different ways enthusiasts interpret a juxtaposition of steampunk and Gothic Lolita. This livejournal community has around 1000 members. There are a lot of for-sale posts here, but also photos and event announcements.
10. The Steampunk Home
Home decor holds a lot of fascination for me, so I absolutely adore this blog. Current posts are talking about the use of globes in office decor; gas-style industrial lights; an acupuncturist's beautiful office; and leather flooring.
11. Steampunk on Facebook
This Facebook group has 17,000 members. With 100 officers, it's well moderated so you'll usually only see on-topic posts.
12. The Clockworkers Guild
A Livejournal community for steampunks. Rather than being full of sale posts, which I dislike in communities, the posts here are showing interesting things people found online, or advertising upcoming events
13. Antipodean Steampunk Adventures
An Australian steampunk gadget inventor's blog. "Follow the adventures of the maduncle as he builds strange new devices in his attempts to contact the steampunk engineers in the mother country." He's currently working on a prosthetic peg leg.