Methods and systems for determining past activities of a user and triggering an action accordingly are disclosed. In one aspect, the method is performed on a device and involves determining a set of historical information related to past activities of the user, according to at least one sources of historical data available through the device, determining a timeline of past activities of the user, according to the set of historical information, and triggering an action on the device, according to the timeline of past activities of the user.
Please help me write a proper abstract based on the patent claims. CLAIM: 1. A method for triggering, on a device, an action according to past activities of a user, comprising: during a first step, determining a set of historical information related to past activities of the user, according to at least one sources of historical data available through the device; during a second step, determining a timeline of past activities of the user, according to the set of historical information; and during a third step, triggering an action on the device, according to the timeline of past activities of the user; wherein during the second step, the timeline of the past activities of the user is determined by: determining a first list of important places where the user went previously, according to the set of historical information; determining a second list of likely complete visits for which at least an associated period and at least an associated location have been identified, according to the set of historical information; determining a third list of candidate visits for which at least a hint of an associated period and at least a hint of an associated location have been identified, according to the set of historical information; for each candidate visit of the third list: obtaining a candidate place associated to said candidate visit; searching for an important place of the first list matching the candidate place; and if an important place of the first list matches the candidate place, replacing, in said candidate visit, the candidate place by said important place, and moving said candidate visit from the third list to the second list of likely complete visits; and determining the timeline of the past activities of a user, according to the second list of likely complete visits. 2. The method of claim 1, wherein the at least one source of historical data comprises a source of time based events, stored by or accessible through the device. 3. The method of claim 2, wherein the historical information related to past activities of the user determined according to the source of time based events is filtered so as to keep only at least one of: historical data extracted from a personal calendar of the user; and historical data comprising information related to a location. 4. The method of claim 2, wherein the historical information related to past activities of the user determined according to the source of time based events is filtered so as to keep only historical data comprising information related to a location and meeting a criteria based on the likeliness that the user participated to the corresponding event. 5. The method of claim 1, wherein the at least one source of historical data is a source of transaction records, stored by or accessible through the device. 6. The method of claim 5, wherein the historical information related to past activities of the user determined according to the source transaction records is filtered so as to keep only historical data comprising information related to a location. 7. The method of claim 1, wherein the at least one source of historical data is a source of media, stored by or accessible through the device. 8. The method of claim 7, wherein the historical information related to past activities of the user determined according to the source of media is filtered so as to keep only historical data related to media produced by the device or another device associated to the user. 9. The method of claim 1, wherein the at least one source of historical data is a source of informal communications, stored by or accessible through the device. 10. The method of claim 9, wherein the historical information related to past activities of the user determined according to the source of informal communication is filtered so as to keep only historical data comprising information related to a location and a date. 11. A non-transitory computer readable storage medium comprising a set of instructions which, when executed by a processor, cause the processor to implement the method of claim 1. 12. A device, comprising: means for determining a first set of historical information related to past activities of a user, according to at least one source of historical data through the device; means for determining a timeline of past activities of the user, according to the first set of historical information; and means for triggering an action on the device, according to the timeline of past activities of the user; wherein the means for determining a timeline of past activities of the user, according to the first set of historical information, are configured to: determine a first list of important places where the user went previously, according to the set of historical information; determine a second list of likely complete visits for which at least an associated period and at least an associated location have been identified, according to the set of historical information; determine a third list of candidate visits for which at least a hint of an associated period and at least a hint of an associated location have been identified, according to the set of historical information; for each candidate visit of the third list: obtain a candidate place associated to said candidate visit; search for an important place of the first list matching the candidate place; and if an important place of the first list matches the candidate place, replace, in said candidate visit, the candidate place by said important place, and move said the candidate visit from the third list to the second list of likely complete visits; and determine the timeline of the past activities of a user, according to the second list of likely complete visits.