1. A method for saving building energy consumption by obtaining at least one energy use strategy in association with a current or future activity in a building, comprising: aggregating activity data from at least one system associated with said current or future activity, wherein said activity data is anonymized before being aggregated, wherein said one or more systems comprise a collaboration software system, the anonymizing retains information including a number of attendants, activity categories information, and activity duration information; estimating an energy demand level based at least on said aggregated activity data; and generating at least one energy use strategy based at least on the estimated energy demand, the at least one energy use strategy is based on the priority of said activity, wherein the at least one energy use strategy excludes considering devices having a fixed energy consumption, wherein executing the at least one energy use strategy is in response to a demand side management request such that said devices can be adjusted continually, further comprising: upon receiving said demand side management request, selecting from said plurality of energy use strategies, at least one energy use strategy suitable for a particular selected time line; determining at least one device to be adjusted in said building; generating a control command for lowering at least one load related to said device to be adjusted; sending said control command to said device to be adjusted; adjusting said device correspondingly; and receiving feedback in response to said demand side management request, wherein the feedback includes information associated with adjusted devices.