1. A computer-implemented method, comprising: comparing, using one or more processors, a first search result with a second search result to automatically identify from, the first search result at least one data item that is new or modified as compared to the second search result, the first search result comprising a first set of data items satisfying a first set of user-specific search criteria and the second search result comprising a second set of data items satisfying a second set of user-specific search criteria; and sending a notification of a result of the comparing to a user device.
1. A computer-implemented method, comprising: comparing, using one or more processors, a first search result with a second search result to automatically identify from, the first search result at least one data item that is new or modified as compared to the second search result, the first search result comprising a first set of data items satisfying a first set of user-specific search criteria and the second search result comprising a second set of data items satisfying a second set of user-specific search criteria; and sending a notification of a result of the comparing to a user device. 2. The computer-implemented method of claim 1 , wherein the first and second user-specific criteria comprises at least one of a search identification (ID), a user identification (ID), a user e-mail address, a category indicator, a search frequency, a minimum bidding price, a maximum bidding price, a description, an order of search result, a search starting date, or a search ending date.