Update: The New York Times has noticed Seattle’s “extraordinary year for moss!”
Our news partner The Seattle Times has a story with this telling headline: “The Seattle region’s coldest April on record is a boon for moss.”
No kidding. 
On the other hand, the Times seems to like it:
Our crummy spring is a glory for that signature denizen of Seattle: moss. The glorious green yang to our gloomy gray yin, moss is reveling in all this cool, moist weather.
Me, I’d rather it wasn’t on my roof.
Got any good moss gripes or photos? Send them our way.
sorry… scepticism
@Let Me Google That…:I can google “male enhancement” but I don’t believe a single result. Data produced by commercial entities with something to gain should always be confronted with sceptisium.
I can not find a scientific/academic study with empirical data showing moss on non-wooden roof will require premature replacement.
Our lawn is moss and dandelions. Sigh.
@Jim: actually, moss isn’t harmless. There are worse things to happen to your roof (trees, small aircraft, etc), but anything holding water to shingles, etc, will eventually damage the roof / shorten its life, especially when we hit freezing temps.
Why remove the moss in the first place? Vanity? Unless your roof is wooden the moss is harmless.
Watch out for the vinegar run off killing your desired plantings.
You can get rid of the moss with a water/vinegar mix… Ask Cisco!