Tags
Tags are coloured labels for grouping hosts – by data centre, by customer, by how much sleep you would lose if they went down. They appear beside host names in the table and tile views, and you can filter on them.

The tag catalogue
The Tags tab holds every tag you have. + creates one, asking for a name and a colour; × deletes it and takes it off any hosts that were using it. The swatch on each chip is what you see everywhere else in the application.
Assigning tags
Tags go on hosts in the Edit Host dialog, where the Tags strip lists your whole catalogue. Click one to toggle it – assigned tags are filled with their colour, the rest are outlines.
Filtering
As soon as any tag is in use, a filter bar appears above the table and tile views. Click a tag to keep only the hosts carrying it, click again to let the rest back in, and combine tags to narrow things further. Each view keeps its own filter, so the table and the tiles can stay focused on different things.
An IT contractor might watch hosts for half a dozen clients from a single window. Create a coloured tag per client – Acme, Beta Ltd, and so on – and assign it to each of their hosts. Before a status call, click that client’s tag in the filter bar and the list collapses to just their network. The colours also make a mixed list easy to read at a glance: all the blue chips belong together.
Not every host deserves equal attention. Tag your must-stay-up hosts as Critical and the rest as Routine. Filtering to Critical gives you a focused board for the things that really matter, while the full list is a click away when you have time for a broader sweep.