In 2008, productivity suite empire Zoho launched a simple invoicing tool, unsurprisingly called Zoho Invoice. Today, the startup is releasing a new version of its Invoice, dubbed Invoice 2.0, that has a fresh user interface and provides a more open application.

The fact is that over the past two years, there have been a plethora of online invoicing startups that have popped up and Zoho is catching up to its competitors with version two of its offering. With this update, Zoho has redesigned its UI making it easier to navigate and customize to fit the look and feel of a business’ design. Zoho Invoice will also allow users to record separate expenses they incur while serving particular clients (like travel, material etc).

The version also has full organization, multi-user support so that several employees can access and collaborate on invoices for a particular account. And Zoho has opened up the API for Invoices to that developers can integrate the application into their own applications. Additionally, Zoho features useful bells and whistles such as multi-currency support and email history which tracks your email exchanges with your clients and other users.

The plus of using Zoho’s invoicing application is that it ties into its other productivity applications seamlessly. And its affordable, with a free version and the most expensive version coming in at $35 per month. Last year, we wrote that Zoho has continued to implement an intelligent strategy to launch new products and add-ons to its existing offerings, partly to keep users from flocking to Google Apps and Microsoft’s Web-based version of Microsoft 2010. It looks like Zoho is continuing this strategy in 2010.

Last year, startup unveiled a new version of Zoho Reports; launched a deeper integration with Google Docs; rolled out Zoho Discussions, a online forum tool for businesses; and debuted Zoho Recruit.

And over the past two years, Zoho has added support for Sharepoint, mobile, Google and Yahoo IDs and group sharing. According to out latest states, Zoho has definitely reached over 2 million users is even catching the attention of its competition. Hopefully, 2010 will be as fruitful as 2009.

Piazzza is still in a private beta and has quite a ways to go before public launch, but we got a sneak peek at its current progress. The site is designed to help classmates share their questions and answers in a format that’s a bit like a mixture between a wiki and a forum. Each class gets its own hub for Q&A, and students can bookmark any questions if they’re also eager to find out the answer. Multiple students can contribute to each answer in a wiki style but there’s a version history that shows what each student wrote.

Students are free to independently create Piazzza hubs for their classes, but I suspect the site will get more traction if it gets professors to sign up. When a professor joins Piazzza, their answers are separated from the students’ to make them easier to find. And professors can also look to see which questions have been bookmarked by the most students to gauge which topics they should explain better in class. So far Piazzza has opened to around 600 students across 9 classes, and plans to open to around 50 classes in a few months. Initial response from professors has been quite positive. And I liked what I saw from the service, though I think it needs to build out some technology that would make it harder to reproduce. I also think that Piazzza will really need to get a large number of professors using the service, which will be difficult.

Nath says that Piazzza was inspired by her own personal experience. As a student studying computer science at India’s prestigious IIT Kanpur, she found herself to be one of only three female students in a class of fifty. She says she was a bit shy and never really got to know many of her classmates, so when it came time to study, she didn’t get to bounce ideas off her peers. After working at Oracle, Kosmix, and Facebook, she’s now a Stanford MBA student.