Abstract: In part, the invention relates to systems and methods suitable for operating a client side platform for deterministically correlating a unique mobile user across multiple marketing communication channels using a universal identifier to provide a deterministic mapping of individual channel user identifiers. In an embodiment, the invention relates to systems and methods suitable for operating a client side platform for probabilistically correlating a unique mobile user across multiple marketing communication channels to provide a mapping of individual channel user identifiers. The systems and methods can be used to identify user activity across different marketing communication channels accessed with a given mobile device.