Your comment made me check whether it was MS that started HTML e-mails. Well, this doesn't seem to be the case, unless I'm missing something. According to wiki

Your comment made me check whether it was MS that started HTML e-mails. Well, this doesn't seem to be the case, unless I'm missing something. According to wiki, only Outlook 98 added support for HTML emails[0]. It's not difficult to find Outlook 97 users asking how to support HTML[1], so the wiki changelog doesn't seem to be wrong. Outlook 98 was released in June 1998. Outlook Express doesn't change this picture - version 4 didn't have HTML email support[2], and version 5 was only released in 1999. MS support date appears to be June 1998. Meanwhile, Eudora 4.0 release announcement[3] at December 97 already mentions HTML support. So at the very least, Eudora had it first. [0] https://en.wikipedia.org/wiki/Microsoft_Outlook#cite_ref-11 https://en.wikipedia.org/wiki/Microsoft_Outlook#cite_ref-11 [1] https://www.excelforum.com/excel-general/396121-outlook-97-mail-format.html https://www.excelforum.com/excel-general/396121-outlook-97-m... [2] https://en.wikipedia.org/wiki/Internet_Explorer_4#Bundled_and/or_integrated_software https://en.wikipedia.org/wiki/Internet_Explorer_4#Bundled_an... [3] https://www.qualcomm.com/news/releases/1997/12/08/qualcomm-ships-eudora-pro-e-mail-40-windows https://www.qualcomm.com/news/releases/1997/12/08/qualcomm-s... Rich HTML Messages - Users have the ability to view and compose rich HTML messages, using graphics and stylized text. Emails containing HTML look as if they would on a web browser and include graphics such as embedded images, tables and java applets.