When deciding what customer issues to focus attention on, most companies naturally choose their biggest, most important issues first. Usually using the number of support calls or warranty cost as the criteria for ranking, they will focus on the few issues that account for the bulk of their support. 
The success of this approach relies on the 80/20 or Pareto rule: the idea that 20% of customer issues will account for 80% of the cost. Most people with business experience know the rule is applicable in many situations: the top 20% of customers account for 80% of sales, 20% of the steps in a project will account for 80% of the work, 20% of the products on the shelf account for 80% of revenue, and so on. And in many cases, the distribution is sharper than 80/20: it can be 90/10 or even 95/5 just as easily.
When customer support issues have this kind of a ratio, it is very easy to decide what to do. The traditional top issues approach says that a company should focus on addressing critical few issues: pick the top five or ten issues, and then focus all effort to resolve those underlying issues: improve the product, improve the help, add online help, or create a frequently asked questions list.
But over time, this approach has become less effective for a variety of reasons. Today, many large companies will find that it is uncommon for any single customer issue to be responsible for more than 1% of calls or support cost. Therefore, even a massive effort to address the ten largest support issues would result in a less than 10% reduction in support calls. Since the traditional top issues approach to addressing issues usually relies on a relatively large investment per issue addressed, it’s not possible to simply take the existing methods of addressing issues and extend them arbitrarily deep into the prioritized list of issues. 
A new approach is needed.
Although I won’t get into the details of this approach in this post, here are a few hints: We will draw inspiration from a parallel in product sales called The Long Tail. Chris Anderson first drew attention to the concept with an article in Wired magazine, and then later a best selling and influential book. Chris Anderson analyzes how three key forces enable sales of even minor products, in aggregate, to outsell blockbuster products. We’ll apply those same three forces to customer support. And no surprise: we’ll end up squarely in the realm of Support 2.0.