The word "dotcom" refers to a website that is part of the commercial sector on the internet. It typically represents a business or organization that operates online as a primary source of revenue. Full definition
The quoted LongFin comment is taken from a December 18, 2017 Financial Times article titled, «Blockchain fervour evokes memories of dotcom bubble». (oakmark.com)
A lot of dotcom companies were forced to balance running both online channels and physical fulfillment. (dailybitcoinnews.com)