Surely it will be on the album when it comes out, so anyone who wants it will get it then. It is not like you get a discount off the album coz you already have one song.
Downloads now count towards a chart position so maybe there's reasoning there. A lot of bands/artists now go down this rout . Radiohead did it for a whole album , asking downloaders to contribute what they thought they should pay.
i like the new coldplay single although it does sound very much like Peter Gabriel early 80's stuff.
If it's as utterly dull and depressingly "wanna be radiohead, except all I can write is talentless piano-based riffs" then a freebie is probably the best chance of getting it anywhere.... A-, E7, A-, anyone? (other than muse?)