I walk by this all time at the corner of Dartmouth and Marlborough Streets:

I have no idea what it is. I see similar things like it elsewhere in the city. It doesn’t appear to be hooked up to any power source. It’s made out of metal, not wood. Is it some kind of billboard that the city has decided to shutter?
Discuss.
Update: Apparently, this is a telecommunications node.

Dunno. If I had to guess, I’d say perhaps a “you are here” map of the neighborhood, but the map hasn’t gone in yet(?).
I think it’s a junction panel for some sort of communicaiton wiring that goes down on of the legs but I can’t see the legs clearly in the picture. At least that’s what I remember thinking when I was last in Boston.
Telephone wiring – they’re a mess when they get hit by cars. Saw one in JP last spring.
Yep, it’s for the telephone and more commonly, DSL access
I thought it was the first wall of a pissoir, and Boston was finally getting public lavatories (although very primative ones).