Streaming FLAC requires more bandwidth, From: "The possibility of streaming FLAC music?" (95114) Options

[extrabigmehdi]

Streaming flac would theoretically take too much bandwidth. It's quite rare that you see people able to ABX a 320 kps encoded file ( and I mean with good encoders like Lame) , from lossless .
Even 320 kps is an overkill most of the time. Similarly , for the digital television , data is compressed before you receive it , in order to save some bandwith.
Never I've seen anyone complaining of the compression artifacts while looking at a digital TV.

[yourlord]

I've seen questions like this before and my simple answer is yes, you can stream FLAC..

But, I would ask that you not do so. Wasting bandwidth on the internet at large is not a practice I'm fond of.. You're free to do so, but it contributes to congestion and simply gives ISP's more ammo to use in their excuses to start metering internet service. You can stream mp3 or Vorbis and use a fraction of the bandwidth a FLAC file would and have a perceptually identical listening experience.

If you plan to actually transfer a copy of the song to the client for repeated use, then by all means send a FLAC. But, for on the fly listening that isn't intended to be kept on the client, FLAC is a waste of network resources.