The growing popularity of online services and IoT platforms along with increased developer's access to devices and services through RESTful APIs is giving rise to a new class of frameworks that support trigger-action programming. These frameworks provide an interface for end-users to bridge different RESTful APIs in a trigger-action model and easily create automated tasks across diverse platforms. Past work has characterized the space of user-created trigger-action combinations in the context of IFTTT, a popular trigger-action framework. In this work, we characterize the space of possible functionality that such frameworks open up to end-users in the context of two major frameworks -IFTTT and Zapier- and discuss results from our comparative analysis of these frameworks. We create a snapshot of 6406 triggers and actions from 1051 channels/apps across these two frameworks and compare the available functions, distribution of channels, and functions shared between them. We examine user's ability to define their own channels, triggers, and actions; analyze the growth of these frameworks; and discuss future research opportunities in this domain.