I first heard about Mint, an online personal finance application, nearly a year ago when it was named “Best Presenting Company” at TechCrunch 40. This fall, Mint will be celebrating their one year anniversary, coming out of beta and rolling out a more robust investment management section on the site.

Last week, I had the pleasure of sitting down with Aaron Patzer, the founder and CEO of Mint. He told me how he got started with Mint and he also presented the features of the site. Aaron Patzer’s background is more techie than financial. He started in web development while still a teenager and graduate from Duke University with a degree in engineering. Always concerned with both his business and personal finances, he had used Quicken and Microsoft Money to manage his account, but he grew frustrated with how much time he had to spend weekly updating his accounts. Aaron decided to develop a efficient solution for managing your money by creating Mint.

Mint is a quick and easy way to have all of your accounts (bank, credit cards, student loans, 401Ks, and investments) in one place so you can see what is going on with your money. In the “Trends” section of Mint, there are pie charts and graphs that actually give you visual to see if you are saving more than you are spending, and where your money is being spent. The dashboard gives you an overview of all your accounts that you have added to your Mint, so the more information you give, the more it can help you manage your finances.

The “Ways To Save” section of Mint advises you on how to save money. It is kinda like a “Consumer Reports 2.0″ since it gives personalized comparisons based on your spending habits.

Aaron demonstrated the new features of the investment section (rolling out this fall) which can show how your investments (401(K), mutual funds, etrade, etc.) are doing. It can so highlight the “hidden maintenance fees” and compare funds so that you can make an informed decision on whether to change the mix of your investment accounts.

I asked about reporting features, and Aaron showed me that transactions can be exported into a .csv file which can uploaded into Excel. Many of the 400,000 users of Mint use it mainly for personal finances. However, some professionals use Mint to track reimbursable expenses for their expense reports, and some entrepreneurs use Mint to track business expenses.

Mint is free, so what is their revenue model? Instead of the usual online ad revenue, Mint has developed affiliations with several financial service companies and Mint’s revenue will be from lead generation from recommended financial services’ product offerings.