A system comprising: one or more processors; and a memory coupled to the processors comprising instructions executable by the processors, the processors being operable when executing the instructions to: receive from a mobile communication device (102, 400, 700) one or more sensor signals indicative of motion associated with activities of a user of the mobile communication device (102, 400, 700); by a pre-classification module (806, 906), select from a plurality of activity categories a particular activity category that corresponds to at least a portion of the sensor signals, wherein each of the activity categories comprises one or more activity types and is characterized by motion that the activity types in the activity category have in common; by a plurality of classifier nodes (808, 910, 912), determine, by using a first analysis algorithm, from among only the activity types in the particular activity category one or more likely activity types of the user by: analyzing the sensor signals against each of the activity types in the particular activity category; and calculating a probability of each of the activity types of the user based on the analysis; send the likely activity types to the mobile communication device (102, 400, 700); request from a user of the mobile communication device (102, 400, 700) a confirmation whether or not the likely activity types represent a correct analysis, and, in response to receiving a user confirmation from the mobile communication device (102, 400, 700), prioritize a second analysis algorithm over the first analysis algorithm, wherein the determining priority is based on determining, based on the user confirmation, that the second analysis algorithm is more accurate than the first analysis algorithm. one or more processors; and a memory coupled to the processors comprising instructions executable by the processors, the processors being operable when executing the instructions to: receive from a mobile communication device (102, 400, 700) one or more sensor signals indicative of motion associated with activities of a user of the mobile communication device (102, 400, 700); by a pre-classification module (806, 906), select from a plurality of activity categories a particular activity category that corresponds to at least a portion of the sensor signals, wherein each of the activity categories comprises one or more activity types and is characterized by motion that the activity types in the activity category have in common; by a plurality of classifier nodes (808, 910, 912), determine, by using a first analysis algorithm, from among only the activity types in the particular activity category one or more likely activity types of the user by: analyzing the sensor signals against each of the activity types in the particular activity category; and calculating a probability of each of the activity types of the user based on the analysis; send the likely activity types to the mobile communication device (102, 400, 700); request from a user of the mobile communication device (102, 400, 700) a confirmation whether or not the likely activity types represent a correct analysis, and, in response to receiving a user confirmation from the mobile communication device (102, 400, 700), prioritize a second analysis algorithm over the first analysis algorithm, wherein the determining priority is based on determining, based on the user confirmation, that the second analysis algorithm is more accurate than the first analysis algorithm. receive from a mobile communication device (102, 400, 700) one or more sensor signals indicative of motion associated with activities of a user of the mobile communication device (102, 400, 700); by a pre-classification module (806, 906), select from a plurality of activity categories a particular activity category that corresponds to at least a portion of the sensor signals, wherein each of the activity categories comprises one or more activity types and is characterized by motion that the activity types in the activity category have in common; by a plurality of classifier nodes (808, 910, 912), determine, by using a first analysis algorithm, from among only the activity types in the particular activity category one or more likely activity types of the user by: analyzing the sensor signals against each of the activity types in the particular activity category; and calculating a probability of each of the activity types of the user based on the analysis; analyzing the sensor signals against each of the activity types in the particular activity category; and calculating a probability of each of the activity types of the user based on the analysis; send the likely activity types to the mobile communication device (102, 400, 700); request from a user of the mobile communication device (102, 400, 700) a confirmation whether or not the likely activity types represent a correct analysis, and, in response to receiving a user confirmation from the mobile communication device (102, 400, 700), prioritize a second analysis algorithm over the first analysis algorithm, wherein the determining priority is based on determining, based on the user confirmation, that the second analysis algorithm is more accurate than the first analysis algorithm.