I don't think there have been unprecedented tax increases, but there may have been unprecedented tax bill increases for some commercial properties. A bunch of properties were reassessed this winter at significantly higher values and consequently, tax bills skyrocketed.

Here's an article from the Patch in early January. (http://somerville.patch.com/groups/politics-and-elections/p/davis-square-restaurants-see-monster-tax-increase-say-aldermen)