Content fetching by mobile device selected based on battery charge level

A method for use with a group of client devices that are each connectable to the Internet by using a wireless network connection, that are each addressed by a respective Internet Protocol (IP) address, that are each configured to function as a proxy device, and that are each associated with a respective numerical or character set value that corresponds to the proxy device functionality, and for use with a content identified by a content identifier, the method comprising:

• storing, by a first server, a list of at least 10,000 IP addresses of the client devices in the group and the values associated with the client devices in the group;
• receiving, by the first server from an additional client device over the Internet, initiated by the additional client device, an additional value associated with the additional client device;
• adding, by the first server, in response to the receiving of the additional value, an IP address of the additional device to the list;
• storing, by the first server, the received additional value;
• receiving, by the first server, the content identifier;
• identifying, by the first server, a first value;
• selecting from the list, by the first server, a first IP address associated with a first client device that is associated with the first value;
• selecting from the list, by the first server, a second IP address that is different from the first IP address and is associated with a second client device that is associated with the first value;
• sending, by the first server to the selected first client device over the Internet, by using the first IP address, the content identifier;
• receiving, by the first server from the selected first client device over the Internet, the content, or an error indication, in response to the sending of the content identifier to the selected first client device;
• sending, by the first server to the selected second client device over the Internet, by using the second IP address, the content identifier;
• and
• receiving, by the first server from the selected second client device over the Internet, the content, or an error indication, in response to the sending of the content identifier to the selected second client device,
• wherein the list comprises at least 10,000 IP addresses.