Coworking operators such as WeWork have been aggressively filling space in New York and may serve as a harbinger for what’s to come in Philadelphia. In recent months, WeWork has been taking leases of large amounts of space ranging from 115,000 square feet to 236,000 square feet. WeWork now occupies 5.3 million square feet in Manhattan and said in its company blog that it is the largest private occupier of space in London, Washington, D.C., and Manhattan.