Trying to figure out which social bookmarking sites to use can rapidly become overwhelming with the sheer number of choices available. To make things a little easier, I’ve narrowed them down to 15 sites that really are worth checking out.

1. Digg
Despite complaints about the notoriously short attention span of the majority of Diggers, this remains the number one social bookmarking site.

2. StumbleUpon
A friendlier way to connect with people and share favorite sites, StumbleUpon is easy to use and a true social bookmarker.

3. Propeller
One of the best sites for business use, Propeller tends to focus on sites of interest to older males in business for themselves.

4. Del.icio.us
Del.icio.us is the oldest bookmarking site around, but that doesn’t mean it’s out of date. Millions of people use it still and the site has a simple, easy to use format.

5. Blinklist
This social bookmarking service is well used and tends to focus on marketing and media, with no restrictions as to which webpages you can tag.

6. Reddit
Offering a personalized groups feature where you can save sites for those in your group to see, Reddit is an oldie, but a goodie.

7. Blipoo
If you are looking for a site that allows self-promotion, Blipoo is the place for you. The site leans heavily toward blog promo.

8. Buddymarks
This site offers three options for saving your bookmarks, personal use only, sharing within a group, or open social bookmarking.

9. Diigo
Hailed as “social bookmarking on steroids”, this site offers heavy duty bookmarking options for the serious surfer.

10. Yahoo! Buzz
This site works similar to Digg in that you can vote your favorite sites up and the worst ones down, plus the Yahoo name makes it a little more valuable.

11. Slashdot
Perfect for bookmarking technical information, this site also has clout with Google, making it a good place for tech business news.

12. Mixx
Here’s a site that is multi-purpose, allowing for submission in a wide range of categories to be voted for by users.

13. Furl
Furl has plenty of Google juice and for this reason, it’s a fairly popular choice among marketers and internet based businesses.

14. PlugIM
A site that offers bookmarking services to internet marketers and lets you submit content, vote stories up and make friends for a full networking experience.

15. ListerLister
Our final social bookmarking site, ListerLister is a site that not only promotes bookmarks, but forming communities based on common interests.

Which social bookmarking sites do you use and what is your favorite?