I am looking for some clarification. I have been reading about installing an exhaust fan in a bathroom, and I have been reading that you should always vent to the outside, but I continue to read that you should never vent through the soffit. 
I am not really sure what this means. Do they mean that you should not put the vent up to the soffit and hopes that it will go out, or do they mean that you should not even use a Soffit Vent designed for this.
I keep seeming devices like these [Bathroom soffit vents](http://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=Bathroom+Soffit+Vent+-+White) and [these](http://store.dryerbox.com/Bathroom-Soffit-Vent--White_p_27.html) which appear to be vents that get installed into the soffit, and then allow you to vent directly to the outside. 

These devices seem like they would work, are these devices acceptable?