I'm trying to promote my website by social bookmarking the content on my site? Which social bookmarking site should I spend my time on? And does anyone have any tips on the best practices or strategies for this type of search engine

I am not sure it's worth the time Unless you automate it a little using tool like Bookmark Demon (Note, I have not tried this tool myself, just heard it was good) But I have begun using Twitter (You can see that if you tweet any microsystools.com or webhelpforums.com page you are automatically recommended to follow me. But it's still *very* new Twitter account, so not much followers)

Anyways Facebook, Twitter, Stumpleupon, Delicious, Digg are my favourites after I did some research on which place likely to have the brightest future

Here are some of the more popular social bookmarking sites:

1. Digg
2. Del.icio.us
3. StumbleUpon
4. Reddit
5. Squidoo
6. Furl
7. BlinkList
8. Blogmarks.net
9. Ma.gnolia
10. Simpy
11. Spurl
12. BlinkBits
13. Shadows
14. Raw Sugar
15. Yahoo MyWeb

# Allmyfavorites  - Create an organized page for your bookmarks that you can share with friends and family, access from any computer.
# Backflip – Check out the most popular links each day, set "The Daily Routine" as your homepage so you can visit your must stop sites each day
    with ease.
# Barksbookmarks – is a website that combines social bookmarking, blogging, RSS, and non-hierarchical editorial control.
# Bibsonomy - BibSonomy is run by the Knowledge Data Engineering Group of the University of Kassel, Germany. Its specifically designed for
    researchers, in sharing bookmarks and bibliographies.
# Blinklist – Social bookmarking with slick interface and new ways for organizing tags.
# Blinkpro – Dynamic folders, bookmark all links of a page plus all the usual features.
# Blipoo - Meet Blipoo, a social bookmarking site for "cool" people sharing "cool" stories. It claims to help bloggers drive more traffic to their blog   
    because they allow self promotion..
# Blogbookmark – Designed specifically for Blog hunters, BlogBookmark.com claims to have the hottest news, gossip, and blog chatter from around
    the web. I highly suggest that mainstream bloggers bookmark their entires here.
# Blog-buzz – Similar to Digg, but for blog posts.

I am also doing social bookmarking for my site.There are Lot's bookmarking site but I like Digg the most.

I like Digg the most.Because it's having 8 PR as well as very popular.

Its true Digg is one of the best for social bookmarking but got problem while using.Am not happy with this site. I like to use
StumbleUpon
Reddit
Squidoo
Blogmarks.net
BlinkBits
As par my view Reddit is best.

Great thread!
Thanks a lot bebo, you had shared a pretty good list in here. I specially follow stumbleupon for social bookmarking.

I think all social bookmarking websites are important. All give us back link and some traffic. So it doesn't matter much that in what you bookmark your website.

I think faves, diggo, digg and stumbleupon are one of the important social bookmarking sites.

I think you can try this list once and some are new bookmarking sites here:

   1. Jim's Free Links (New!)
   2. Digg [V] (
   3. Path to Tomorrow's Links (6)
   4. Odtub KFT Links (6)
   5. Folkd [V] (6)
   6. Kwoff (6)
   7. Ebaum's World (6)
   8. NM Voicemail Links/a> (5)
   9. Life Begins at Conception (5)
  10. ACF Columbia Links (5)
  11. ArizonaTech Bookmarks (5)
  12. Touch the Drop Links (5)
  13. Argenweb Bookmarks (5)
  14. Sugar Symposium (5)
  15. Sweetener Symposium (5)
  16. You Strip Bookmarks (5)
  17. LinkaGoGo (5)
  18. SpotBack (5)
  19. A1 Webmarks (5)
  20. Tagza [V] (5)
  21. Plime [V] (5)
  22. So Force [V] (5)
  23. Xtra Space for Bookmarks (4)
  24. Glasnik Bookmarks (4)
  25. Matamosa Tuvieja Links (4)
  26. Miami Party Bookmarks (4)
  27. IM Translation Links (4)
  28. Rolegame Bookmarks (4)
  29. Revenue Workshop Links (4)
  30. Online NAMeeting Links (4)
  31. Feedmarker (4)
  32. OYAX (4)
  33. Cool Search [V] (4)
  34. Garcia Web Links (3)
  35. Watch Movies & Store Links (3)
  36. Leech Tamer Links (3)
  37. Mix 957FM Links (3)
  38. MyLinkVault (3)
  39. Yattle (3)
  40. Bukmark [V] (3)

Hope this may help you...

Stumble Upon, Digg, Digoo, Reddit, Friend Fister, etc. these are some social site which have great visitors and also help in fast indexing your web page.

In my opinion stumbleupon and digg are the best social bookmarking website. It gives better response to us.

Here is a big list

google.com/bookmarks
slashdot.org
digg.com
stumbleupon.com
squidoo.com
reddit.com
mixx.com
technorati.com
folkd.com
mister-wong.com
delicious.com
my.aol.com
propeller.com
metafilter.com
diigo.com
wikio.com
blogcatalog.com
blinklist.com
newsvine.com
bibsonomy.org
connotea.org
sphere.com
citeulike.org
hotklix.com
jumptags.com
dzone.com
sphinn.com
linkagogo.com
mylinkvault.com
buddymarks.com
simpy.com
allvoices.com
simpy.com
spurl.net
kirtsy.com
twine.com
startaid.com
weheartgossip.com
bookmarks.com
indianpad.com
a1-webmarks.com
url.org
bookmarks.oneindia.in
spotback.com
swik.net
corank.com
dropjack.com
searchles.com
tagza.com
designfloat.com
fark.com
blurpalicious.com
faves.com
bharatwaves.com
smallbusinessbrief.com
rambhai.com
oyax.com
quadriot.com
fwisp.com
fazed.org
cadillactight.net
mototagz.com

The best social bookmarking sites for SEO are :
1.Digg
2.delicious
3.twitter
4.blinklist
5.reddit
6.BlueDot

Best Social bookmarking sites are:

1. Digg
2. Technorati
3. Stumbleupon
4. Delicious
5. reditt

so many social book marking sites available already mentioned here, better is to stick to few and make your sites social.

There are so many sites for social bookmarking.
Like Facebook ,twitter,digg,delicous,lindin,
You can go to Socialmaximizer.com for Social bookmarking Link.

The best social bookmarking sites for seo are :
1.Twitter
2.Reddit
3.Squidoo
4.Delicious
5.Clipmarks
6.Lifelogger.

As per my experience facebook and delicious are the best social bookmarking sites for SEO

There are really lots of great socialbookmarking site but these one our my favorites.

1. Digg
2. Del.icio.us
3. StumbleUpon
4. Reddit
5. Squidoo

Hi,
Bookmarking the site on the social bookmarking sites is a very good process to get traffic as well as backlink. This is the easiest way to approach lots of people, but you cannot depend on a single site for the promotion of the website.
I think, bookmarking on the top ranked sites will help a lot to promote the website and generate business through it.

Stumble Upon, Digg, Digoo, Reddit, Friend Fister, etc. these are some social site which have great visitors and also help in fast indexing your web page.

Here some list of famous Social bookmarking..
1. Digg
2. Del.icio.us
3. StumbleUpon
4. Reddit
5. Squidoo
6. Furl

Best Social bookmarking sites are:

1. Digg
2. Technorati
3. Stumbleupon
4. Delicious
5. reditt

I think all social bookmarking websites are important. All give us back link and some traffic. So it doesn't matter much that in what you bookmark your website.

Social bookmarking is one the best activities for generating one way back link which helps to boost website ranking and traffic. For SEO point of view quality site mean high PR and do follow social bookmarking sites are the best that's passes the all benefit to our link or site.

1. Digg
2. Del.icio.us
3. StumbleUpon
4. Reddit
5. friend feed

social bookmarking is very usefull link building technique of off paging seo .it is helpfull in generating backlinks for your site and for bringing traffic for your site. my favourite social bookmarking sites are: digg, reddit.

Best list are shared here.  Thanks for the lists.

Website development los angeles | Web design firms in los angeles

There are allot of social book marking websites:
mister-wong.com
delicious.com
my.aol.com
propeller.com
metafilter.com
diigo.com
wikio.com
blogcatalog.com
blinklist.com
newsvine.com
bibsonomy.org
connotea.org
sphere.com
citeulike.org
hotklix.com
jumptags.com
dzone.com
sphinn.com
Try out these one as i am also going to work on it:)