Sure, you know what those Twitter, Facebook, reddit and Digg icons mean at the bottom of most blog posts these days, but what about all those other funny-looking ones? There's a pantload of them - so many that it can be overwhelming and confusing.
Allow us to break down our 18 favorites for you (click each icon to be taken to their Web site):
1. Delicious
What started out as Del.icio.us has evolved into Delicious.com. One of the better known free social bookmarking sites, Delicious uses tags instead of folders to help you organize your bookmarks. Because they are stored online, your bookmarks are accessible from any computer. You can also share your bookmarks with others, and see what articles are popular for any given topic.
2. StumbleUpon
Like flipping through channels on the television, StumbleUpon allows you to surf the web but only hit the sites that interest you or fit the criteria you choose. The StumbleUpon bar at the top of the screen allows you to stumble to another site, say you like the site, share the site with others, read reviews of the site, or save your favorites. StumbleUpon also can connect with Facebook and has a Firefox add-on.
3. Squidoo
Use Squidoo to find or create useful posts, called lenses, on any topic. By writing on a topic yourself, you share your unique point of view. Ad revenue from ads that are shown on your lens pages makes money, part of which you can donate to a charity, or keep yourself.
4. Kiva
Here's one of my personal favorites! Kiva is a microdonation site that enables you to donate small amounts (or large amounts) of money to help small entrepreneurs with their businesses, all over the world. Your money is grouped with money from others to make a bigger difference. Follow the stories of the entrepreneurs in the Journal section.
5. Diigo
Both a research tool and a social collaborative community, you can use Diigo to organize your bookmarks, archive pages, and annotate each page. You can also share those pages with others, or create a group with which to collaborate. They also offer free educator upgrades to help teachers organize their lesson plans and communicate with their students.
6. Folkd
This social bookmarking site allows you to save and share bookmarks, tag and organize them, access them from anywhere, see what is popular today, and look at friends' bookmarks. Installing the bookmark button in your browser allows for easy adding. Big props to these guys, too, for having one of the cooler icons of the lot!
7. Gnolia
Currently invitation only, Gnolia is a community based on sharing and saving links and bookmarks. With its rebirth in 2009, they have incorporated lessons learned from the old Ma.gnolia service, including keeping the site a manageable size. They hope to encourage the growth of the community through personal connections.
8. Plurk
Plurk is a social network that allows you to share what is going on in your life with others. It is different from other social sites in that it displays your updates, and those of your friends, in a timeline format. Why plurk? We have no idea but it sounds pretty cool!
9. SlideShare
SlideShare is a professional media sharing community in which to share presentations and other documents you create. You can share things such as PowerPoint & Keynote presentations, videos, and Word and PDF documents. You choose how public or private your presentations will be.
10. Plaxo
Plaxo is a socially connected address book site which allows you to access information for your contacts from anywhere. It uses Pulse to connect with places like Twitter, Flickr, and other sites. Plaxo allows you to import contacts from your current contact list, and Plaxo Premium allows you to sync your contacts, calendar, and tasks with Outlook.
11. GratitudeLog
Express your gratitude for people, things, companies, or whatever you are grateful for with GratitudeLog, a social networking site. Add friends to your list of people to follow, and show your appreciation for others.
12. APSense
APSense is an affiliate social network where you can share ideas with other affiliate marketers, find new affiliate opportunities, or advertise your own business.
13. iLike
iLike is a social music discovery site where you can share playlists and music recommendations with others. It is partnered with MySpace Music and can be used on sites such as Facebook, Google, Orkut, and others.
14. deviantART
An online social network for artists and art lovers everywhere, deviantART allows artists to display and promote their own work as well as enjoy work by others. Communicate with other artists in the community, sell your art, or purchase artwork on display.
15. Orkut
Orkut, part of Google, is a social community where you can stay in touch with friends by sharing photos and sending notes, find new friends who share your interests, or develop new professional contacts.
16. Mments
Sick of missing interesting comments on articles you read? Tired of having to keep returning to sites to follow comment threads? With Mments you can bookmark a post whose comments you want to follow. Then track your marked conversations together on one page. You can also follow the comments in email or your feed reader.
17. Kirtsy
A social media site, Kirtsy allows you to connect with others, find information, and discover products. Items are submitted by readers. Clicking on posts that you like will help promote items to the top of the list where they can more easily be discovered by others.
18. Simpy
Simpy is a social bookmarking site that allows you to save, organize, and share your bookmarks and notes with friends or groups that you create. You can import and export bookmarks at any time. Simpy will also detect broken bookmark links.