That's a shame for now, but the fact that related artists are presented very clearly (and you're able to quickly see their most popular songs) doesn't make discovery as bad as the article is claiming. I find myself listening to a lot more different music with Spotify than other discovery services such as Last.fm.
Amounts to browsing random peoples' music. Compared to MOG's discovery features, MOG's is much better. You might get lucky if a friend just happens to find lots of new music you like though.
