I think it would be more feasible to implement a mechanism for ranking posts coupled with a (possibly later) mechanism to view large threads with only higher-ranked posts visible than to try to design a search mechanism that's better than Google's (which I often use to try to find content on FT). I'm not aware of any usable mechanism that can determine context (just as one example, factual information rather than speculation or opinions as to what is desired). Humans are much better at this sort of thing.

Now, this entire endeavor might well be a fool's errand. It's certainly possible that FT is hopeless, that human nature being what it is, the state of FT discussion and usefulness as an information resource can never be decent, and we really should give up on it. Being an optimist, I hope this isn't true, but I'm always willing to believe I'm wrong.