Ze'ev re downgrades....
I have built a database of all upgrades and downgrades over the last 18 months (about 16k, at the moment). I also have subsequent performance data. If ever you want to know how a particular broker has done when making a particular recommendation, I'll be happy to tell you.
BTW, overall, neither downgrades or upgrades are contrary indicators. However, downgrades tend to be less accurate than upgrades (even in a bear market, surprisingly). I think that's because the upgrades are anticipatory, while the downgrades are more likely to be reactive, and the reaction often comes too late.