ITunes match

Just this morning I posted that I expect iTunes match to be released shortly and now it is actually here. I just switched it on on my Mac. Strangely enough there was no iTunes update for me. I am still on 10.5 and as far as I can see nothing happens after turning iTunes match on. Only difference is I can now enable iTunes match on my Apple TV - but I don't see any songs. On my iPhone I enabled it and it told me that my library will be replaced - not sure I see a good reason for that either. Anyway - library got replaced and now I have also here no songs. Only my Audiobooks are still there. I will give it time until tomorrow morning and see what happens.