So hold on a minute, you lied to us in the title, at the end of the day you still need a subscription to listen to music you want on your mobile.
Bit dramatic isn't it?

Yeah I did say in the OP that you still need a subscription to stream any track on-demand. I haven't used the last.fm app to know what the difference is between them, so here's what it can do:
a. You can create stations based on artists (same as Last.fm) but it lets you combine a few artists into a station, so that's a little more flexible. They're as crap as last.fm's though, so sometimes you get something from COMPLETELY the wrong genre in there.
b. It can save those stations for offline playing. I have no idea how it does this, as Android is reporting that its cache is only taking up about 10.5MB, but I've had it play through 20 tracks while the phone was in flight mode so it must be using abysmally low bitrates unless it's storing them someplace else that the Android OS can't see!
c. it automatically generates a custom playlist for your account based on tracks you've added to your favourites either on there or in the desktop version. That's a really interesting option but it seems to be pretty wonky. I haven't been using the "favourites" function at all so far, so I experimentally added a few tracks through the desktop app, then logged into my account on the mobile app to see what it would come up with. I had favourited (is that even a word? OK then, "wubbed") a few classical piano tracks (some Beethoven, some Debussy, that kind of thing) and a few Greek hard rock songs. What the mobile ad played on my personalised radio was Diana Ross and Janet Jackson...

Gonna need some fine-tuning there I think
For the record, I think it's a little cheeky of both We7 and Spotify to differentiate between desktop and mobile versions. If the reasoning is that revenue from ads served on mobiles is lower than on desktops then I can get the necessity for that (say if Google gets a bigger cut, or the mobile operators charge them to carry their data, although I don't think any of them has started doing that yet), but that doesn't justify the £5 ad-free plans from not allowing streaming on-demand to mobile. You're getting my money, you should be providing me the same service from whatever device I'm accessing your service from - it's not costing you more to stream those songs to me through O2's mobile network (I'm on giffgaff) rather than through Virgin's cable. You pay for a service, it should be network-agnostic, just as ISPs and mobile networks should be data- and protocol-agnostic. Those are the pillars of net neutrality, and if we let them take it away from us the internet will collapse into a bland corporation-curated mess. (Which will probably not support Firefox or Chrome and will have a "Works best at 800x600 using Internet Explorer 5.0" message on every page) OK, rant over.
And as a final note, if Pandora were available in the UK I'd happily be payingthem a subscription and not be wasting my time with either We7 or Spotify, regardless of the fact that you can't stream specific tracks on demand through it!
