A method for processing a callback request, wherein said callback request is made by a user computer from a web page provided by a web server, wherein the callback request is for a call to a user of the user computer, representing a first party, from an entity associated with the web server, said entity representing a second party, and wherein said callback request is transmitted from the user computer to a callback call server, said method comprising the callback call server performing the steps of: receiving on a packet switched network comprising the Internet the callback request including information sufficient to identify a device associated with the first party who wishes to receive the call and including information sufficient to identify a device associated with the second party from whom the first party wishes to receive the call, the callback request originating from a source computer, wherein the source computer may be identified based on an IP address or URL associated with the callback request or an identifier of the user computer which is included in the callback request, and wherein the source computer may be the user computer or a computer of a malicious user; deciding whether to block the callback request based on at least one criterion selected from the group consisting of (a) a total number of callback requests received from the source computer during a period of time, (b) a total number of calls resulting from callback requests received from the source computer currently in progress, (c) a total number of callback requests received from the source computer for a call from the second party during a period of time, (d) a total number of callback requests received from the source computer for a call to the first party during a period of time; and (e) a total number of callback requests identifying the device of the first party during a period of time; and connecting the first party to the second party if the callback request is not blocked. receiving on a packet switched network comprising the Internet the callback request including information sufficient to identify a device associated with the first party who wishes to receive the call and including information sufficient to identify a device associated with the second party from whom the first party wishes to receive the call, the callback request originating from a source computer, wherein the source computer may be identified based on an IP address or URL associated with the callback request or an identifier of the user computer which is included in the callback request, and wherein the source computer may be the user computer or a computer of a malicious user; deciding whether to block the callback request based on at least one criterion selected from the group consisting of (a) a total number of callback requests received from the source computer during a period of time, (b) a total number of calls resulting from callback requests received from the source computer currently in progress, (c) a total number of callback requests received from the source computer for a call from the second party during a period of time, (d) a total number of callback requests received from the source computer for a call to the first party during a period of time; and (e) a total number of callback requests identifying the device of the first party during a period of time; and connecting the first party to the second party if the callback request is not blocked.