As an AI language model, I can provide you with a list of popular social bookmarking sites that have historically provided dofollow backlinks. However, please note that the landscape of SEO and link building is constantly evolving, and the effectiveness of these sites may change over time. Additionally, it's important to focus on quality over quantity when building backlinks, as search engines value authoritative and relevant links more than a large number of low-quality links.

Here are some social bookmarking sites that have traditionally provided dofollow backlinks:

• Reddit (Some subreddits provide dofollow links)
• Digg
• StumbleUpon/Mix
• Scoop.it
• Slashdot
• Diigo
• Plurk
• Folkd
• BizSugar
• Delicious
• Flipboard
• Pocket
• MetaFilter
• Newsvine
• Pearltrees

Remember to review the guidelines and rules of each platform before posting and ensure that your submissions are relevant, valuable, and add to the community. Building a diverse backlink profile from a mix of sources, including social bookmarking sites, can be beneficial for SEO, but it's essential to focus on high-quality content and engage in ethical link building practices.

Additionally, it's always a good idea to stay updated with the latest SEO trends and guidelines from search engines to ensure your link building strategy aligns with the best practices for long-term success.