One of the more interesting Web 2.0 applications is 37signals' Basecamp, which is an on-line project management application. 37signals has launched a number of popular and quite useful on-line applications recently including "Backpack," "Campfire" and "Ta-da List." Their success is indisputable. Over one million people have signed up to use Basecamp, and the company's services have been covered by such publications as Business 2.0, the Wall Street Journal and Fast Company.

37signals is a company that understands the utility of business applications, and their design approach is summed up nicely in this brilliant quote: "Projects don't fail from a lack of charts, graphs, stats, or reports. They fail from a lack of clear communication." Brilliant.

But now, 37signals has added a brand new online contact management tool called "Highrise" which is certain to garner its share of attention, especially if it works well alongside Basecamp.

Anyone who works in a business based on conversations with customers or clients knows that keeping track of who said what where and when can be a major problem no matter how many PDAs, computers or mobile phones are thrown at the problem. For some reason, the basics of digital communications are being reinvented by Web 2.0 companies after desktop software's inability to offer something as simple as a really good to-do list. Everyone uses to-do lists. Everyone.

Highrise gives its users the ability to sort conversations into lists, schedules and contacts, keeping track of who was speaking and what they said. Its first and most obvious application will be for salespeople, but as we all know, Web 2.0 applications are not defined by feature lists. They are defined by users who often make use of these new applications in ways that make them more useful for all of us.

Highrise works with e-mail, and can accept tasks via e-mail. It can be used to share conversations and contact information company wide, which helps keep entire teams up to date on what is happening with a particular project. Permissions can be set in order to authorize information among team members. It is even possible to forward e-mail from a particular contact and have Highrise append that e-mail to the contact's page. This may turn out to be its most popular feature very quickly.

Highrise is free for basic accounts, and there are numerous pricing plans up to $150 a month for the "Max" plan with unlimited users.