In the short time that it has been available, I have become a regular user of the Global Web-based English Corpus (GloWbE), and I have encouraged students and young researchers to use it, too. GloWbE is a great new resource, and Mark Davies is to be thanked for making it widely and generously available to a global community of linguists and students of the English language, many among whom will be speakers of the varieties of English documented. Mark and Robert's paper offers a useful summary of the corpus design and architecture and presents a wide range of case studies illustrating the potential of the new resource. I have found the case studies convincing in themselves and also capable of inspiring numerous similar projects. What I find encouraging for future work is that Mark and Robert use GloWbE to replicate numerous studies carried out on small corpora, thus proving the robust reliability of the new resource before they move on to use it in order to explore less well-charted territory. The researcher using GloWbE as a stand-alone corpus to investigate mid-and low-frequency phenomena in World Englishes can thus rest assured that, data-wise, they stand on firm ground. Most grammatical constructions and lexicogrammatical variables distinguishing varieties of English are in this frequency band, and currently only GloWbE provides the amount of data and the convenient and powerful search interface needed for systematic comparison across varieties. "Expanding Horizons" indeed.Against the background of this generally very favourable assessment, and in fulfilment of my role as a constructively critical commentator, I may be permitted to raise a number of points which remain to be addressed.