Add this to the Consumerist toolbelt: Star Raids. If a company is pissing off a bunch of customers and refuses to change some aspect of their product, some consumers are finding it effective to band together and thrash the product’s rating. An avalanche of “zero” ratings can make a ratings score plummet, and turn away potential customers. The fall-off in sales will definitely grab their attention.
These are both pieces of software. The effectiveness is hardly limited to software. The Star Raid was successful because users of those products are more likely to be savvy enough to know the impact of such an attack, and to frequent a user-generated news-aggregation site like Digg or Slashdot where an issue, and call to arms, like this would tend to be publicized. To hand the tool to the broader populace, it just needs to be talked about in broader forums, like this one, natch.
Like the best Consumerist tools, it works because anyone can do it and it directly impacts the corporate balance sheet, which is the best (and often, only), way of getting them to give a damn.
One obvious limitation is that retailers can simply delete the onslaught of negative reviews. However, they do so at their peril. Censoring the angry users will likely only lead to further outcry beyond those initially ticked off, as Amazon also learned with Spore. Another limitation is that the product or service needs to be listed on a site that allows ratings. A subsidiary limitation is that site has to be well-trafficked enough to mater.
However, applied judiciously, it can be very effective.