Ben Horwitz works on startups at OpenAI and created Sinceerly, a Gmail extension that rewrites polished AI drafts into a more informal style. He previously cofounded Causeway and invested through Dorm Room Fund.[1][2][3]
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X · horwitzben Career
Horwitz cofounded Causeway, a charitable-giving platform acquired by Charity Navigator. He then served as Charity Navigator’s vice president of New Ventures. His earlier work included emerging-market growth at Meta and consulting at Prophet. Dorm Room Fund’s biography identifies him as a Harvard Business School MBA student and a Haverford anthropology graduate. A later Haverford event identifies his OpenAI startup work and former investment-partner role.[3][4]
Contributions
Sinceerly runs inside Gmail’s compose window. The user chooses a rewrite intensity and sees changed text highlighted before approving a replacement. Its informal style removes stock phrases and punctuation patterns and can add deliberate mistakes. The product offers a bring-your-own-key path as well as a hosted service. It addresses the tone of a draft; the review step still matters for the meaning of the message.[2]
Tools, writing & talks
Tools
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Sincerelysinceerly.comA Gmail extension for reviewing and applying informal rewrites of email drafts.
Read the example transformations and review controls before installing. It requires Gmail in a supported Chrome environment; compare each highlighted edit with the intended meaning before replacing a draft.
Creator, explicitly named and linked by the product About section[2]Original source