Well, there are certainly many different views on this subject.
What I personally mean by being an urban monk, is that while I live in the city, partake of its various pleasures, I follow the dharma as it unfolds in my heart.
There are a few older practitioners in my neighborhood who live a similar lifestyle, none of us sit with any group now, we meet when it happens on the street,
rather like joining an online community and "connecting" with someone. The Buddha, I have heard, said that it would be better to travel and meditate alone than
to keep company with others who do not share one's view. So it seems that as I age there are fewer and fewer people whom I meet that I can talk with.
Perhaps that is being friendly without clinging...
There are so many ways to be involved with the dharma, so many views...I view my monastery as the city where I Iive, unattached to anyone, friendly to all.