Seafoam consists of:
"40-60%" Pale Oil (lubricant),
"25-35%" Naphtha (thinner, varnish remover), and
"10-20%" IPA (to pull water into mixture).
http://seafoamsales.com/wp-content/uploads/2012/12/MSDS_seafoam_EN.pdf
Seafoam was reportedly concocted for boat motor storage over the winter. The oil is there to coat and lube the fuel-air system so it doesn't rust up or seize during storage. Naphtha is to prevent varnish build up. IPA to mix with water (think condensation, dew, inside the motor) so it can't pool (rust) and can pass through the fuel metering system (carb) without block a jet, which a drop of water can do because it doesn't mix with the gasoline.
Just trying random products until you "think" you can "feel" a result is a great way to make a small fortune... out of a big one, unless you're the one selling the stuff.
Water injection can work, but it must be properly metered and atomized prior to combustion, something few go through the effort to do properly and thus the consistency of their results.