Lately, it's been fun finding niche social sites. However, instead of being limited to sites that interest us, you'd rather go check the lists of social sites and pick the ones that fall in your industry.

12 lists of social sites:

1. Social networking god: 350 categorized social networking sites from Mashable (Oct 2007)
2. Digg-style applications: Hundreds of categorized custom Digg style sites, Pligg-based sites, social sites/networks in foreign languages and so on.
3. 83 social sites: various social sites, cagetorized by the topic. Judging by the size of the list, I'd figure it covers most common topics and the sites have some traffic.
4. Dozens of social sites with PR and Alexa ranks: the list was created by Lyndon Antcliff, one of the better social media experts. Most sites are categorized, some are not. You can use the other lists or see them yourself, I suppose.
5. 38 (and counting) social sites that drive traffic from Andy Hagans: a list of social sites that let you get heavy traffic.
6. 233 social sites: a huge categorized list of sites. I suspect it also includes social networks.
   The directory of Web 2.0 sites of all categories: puts all Web 2.0 sites in voting, bookmarking, networking, sharing and other categories. If you want to see everything, this would be your first stop.
7. 1000 categorized sites on one fast page: I'd suspect it is similar to the previous directory, but it shouldn't hurt to check the industry you are working in, just in case.
8. List of Pligg-based social sites that drive some traffic: I doubt that this is a complete list, but this list is something to keep in mind. Also lists sites by PR, keyword and categories.
9. List of social bookmarking sites: categorized list of apparently inhabited websites.
10. 40 social sites with traffic, reviewed from Dosh Dosh: A run down of main and niche social sites to help you choose and participate there.
11. 139 social sites with PR and topics.
12. Bonus: 15 environmental social sites from Bill Slawski

Liked the lists? Get 10 more lists from Tad.

Will you get traffic from social sites?

You may be thinking that once you have your own list, you'll drown in traffic. Unfortunately, this isn't the case.

To get plenty of traffic, you need to:

know the audience of the social sites, sometimes each site has its own audience and likes (and to know it, you need to get involved with the site for some time) create a piece of exceptionally inspiring, touching or helpful of content, based on the audience's needs/likes/values spend plenty of time on creating a catchy, effective title to get your story voted for write an equally hypnotizing description format the post to actually get read and linked to 'further reading'. If you are not well versed in link baiting, you may want to read linkbaiting articles at Cornwall SEO by Lyndon Antcliff and also site-specific articles about Digg and Stumbleupon.

You may want to read an excellent post, explaining how to create linkbait step-by-step at SEOmoz.

If anything, just read these sites:

Pronet Advertising
Search Engine Land