  One of the key emerging roles of the YouTube platform is providing creators
the ability to generate revenue from their content and interactions. Alongside
tools provided directly by the platform, such as revenue-sharing from
advertising, creators co-opt the platform to use a variety of off-platform
monetization opportunities. In this work, we focus on studying and
characterizing these alternative monetization strategies. Leveraging a large
longitudinal YouTube dataset of popular creators, we develop a taxonomy of
alternative monetization strategies and a simple methodology to detect their
usage automatically. We then proceed to characterize the adoption of these
strategies. First, we find that the use of external monetization is expansive
and increasingly prevalent, used in 18% of all videos, with 61% of channels
using one such strategy at least once. Second, we show that the adoption of
these strategies varies substantially among channels of different kinds and
popularity, and that channels that establish these alternative revenue streams
often become more productive on the platform. Lastly, we investigate how
potentially problematic channels -- those that produce Alt-lite, Alt-right, and
Manosphere content -- leverage alternative monetization strategies, finding
that they employ a more diverse set of such strategies significantly more often
than a carefully chosen comparison set of channels. This finding complicates
YouTube's role as a gatekeeper, since the practice of excluding
policy-violating content from its native on-platform monetization may not be
effective. Overall, this work provides an important step toward broadening the
understanding of the monetary incentives behind content creation on YouTube.
