Presumably he's talking about claimed output powers?, there's often no sense to them - but basically the claims are just ludicrous, with 50W been called 1000W, or even worse.
The ONLY figures worth paying attention to need to be RMS continuous power, with specified distortion and frequency range.
where:
year - every year manufacturers claim that the wattage output is higher
age of the car owner - the younger the driver the more he boast about his stereo.
Take care with rms too mirel, as nige says your only interested in rms, as in root mean square, I have seen a ridiculous rating that also said 'rms', but when I couldnt possibly see why an amplifier could provide way more power than its input fuse was rated for I discovered that the manufacturers where actually quoting 'rms' as 'real music sound' not root mean square.