21 (@21dotco) — Twitter Score 34 out of 1000

21 is a Bitcoin startup that began as a bitcoin mining hardware and software company before pivoting to a paid inbox and micropayment product, and was later renamed Earn.com and acquired by Coinbase. 21's Twitter Score is 34 out of 1000 as of July 2026, ranking #31,800 (top 10%) among 531,432 tracked accounts.

21 was founded by Balaji Srinivasan and raised over $110 million in total venture capital, with backers including Andreessen Horowitz, Khosla Ventures, RRE Ventures, Data Collective, Qualcomm Ventures, and Cisco Investments. In February 2017, the company unveiled a paid inbox product built on bitcoin infrastructure, allowing senders outside a recipient's network to pay to deliver messages. The @21dotco account is now inactive, with activity moved to @21.

21 was formerly affiliated with Earn.com, the name the company adopted before its acquisition. Coinbase acquired Earn.com in April 2018, per Axios, with the total value returned to shareholders exceeding the more than $120 million the company had raised. Balaji Srinivasan joined Coinbase as Chief Technology Officer following the deal. The @21dotco account has 2,825 followers as of July 2026 and 174 posts. 21 has been mentioned by 185 accounts, with 386 total mentions.

Who follows 21 on X?

The accounts that follow 21 include 133 founders, 23 angel investors, 42 influencers and 9 VCs. Among them are Balaji, Fred Ehrsam, Udi Wertheimer, Joseph Lubin, Jesse Powell and Tyler Winklevoss.