The idea is to go to the page of your number one artist, and follow the link of it's number one similar artist, then repeating that for this artist and so on, noting down each artist as you go.
Do this until you've got to 50 artists (not including your number one). If you get any repeats, just go to the second similar artist or the nearest one that you haven't already had.
Lifehouse
1.Goo Goo Dolls
2.Matchbox Twenty
3.Third Eye Blind
4.Eve6
5.Everclear
6.Weezer
7.The White Stripes
8.The Strokes
9.Franz Ferdinand
10.The Killers
11.Snow Patrol
12.Coldplay
13.Oasis
14.Blur
15.The…