Also, yet another article that makes me rethink my choice to take Homological Algebra with no real algebraic topology coursework. Merkurjev was teaching so at least I have all his notes. It kind of forced me to give up any concrete basis and just handle abstract tools.
I urge you to read Hatcher's book (or better, tom Dieck's book published by EMS) immediately. I can't even imagine learning homological algebra without a bunch of concrete topological examples to compute with. That sounds confusing.