One thing I keep in mind when reading these upgrades/downgrades and any other media comments about stocks, is that the major holders of stocks; mutual funds, pension plans, etc, all take a tremendous effort to change their position in a particular stock. Kinda like turning the mega-size cargo ship, takes careful planning and executed over time. Individual investors can be in and out of their tiny position in a heart beat, with no impact to the market.
Having said that, I would assume that by the time the avg. Joe on the street (meaning most of us) hears about these down grades/upgrades, recommendations, etc, the true players on the Street have already made their move and are into or out of the position they want to be at. So, it isn't that they are baiting others to buy the dog they are selling, but they for sure have already bought (or sold, or shorted, etc) the stock they are now commenting on. So they do have a benefit to any upside there.
If a majority of the analysts' opinion is contrary to mine, I at least research why and weigh that against the fundamentals that made me interested in the stock.
I know this because I'm very accomplished at losing money in the market!