Avira 2013 is nearly identical to last year's version, but there are big changes under the hood. (Credit: Screenshot by Eddie Cho/CNET)

The competition for the best free Windows security suite just got a lot more intense, as Avira returns to the field with its second major revamp in as many years of its flagship free antivirus and paid upgrades.

Available exclusively from Download.com today, Avira Free Antivirus 2013, along with the paid upgrades Avira Antivirus Premium 2013 and Avira Internet Security 2013, greatly expand the kinds of protection that Avira offers.

Avira wouldn't reveal a precise number of people who use the suite, but Opswat puts them at around 12.1 percent of the worldwide Windows market. Travis Witteveen, Avira's head of marketing, said during a visit to the CNET offices that Opswat's math was "very close" to the actual number of people using Avira. That's a jump of 2.8 percent since Q1 2012.

Last year's update brought a new interface, a much faster installation, and better overall security. This year, Avira has focused on expanding its security features to cover social networking, tracker blocking, and Web site verification, as well as a huge push into crowdsourced tech support. Longtime Avira Free users no doubt will be delighted that the daily upgrade pop-up will go away permanently if you install the Avira toolbar.

The toolbar has become a major focus for Avira, and the company is using it to provide multiple in-browser security features. The company has partnered with Abine to bolt their Do Not Track Plus tracking and ad blocker to the toolbar. Also in the toolbar is the new Web site reputation adviser, also on loan but from CallingID, and social networking protection courtesy SocialShield, a company Avira bought earlier this year.

A new "Experts Market" is also accessible only from the toolbar. It's crowdsourced tech support, where Avira fans can sell their expertise to others and set their own rates. Witteveen said that the Experts Market is designed to connect tech experts to people who are looking to solve tech problems. These user-experts can then charge whatever sum they'd like for their services, and Avira will take a 10 percent commission.

Avira has changed other parts of the suite, as well. The virus definition file and protection engine now checks for updates every six hours instead of once a day. Premium Avira makes the same check every two hours. There's also an Android app that provides anti-theft and device tracking features. Witteveen said that Avira has plans to include a security engine in it, "probably before the end of the year."

Avira itself felt snappy in preliminary real-world testing, and early results from CNET Labs look like the suite will be highly competitive on a performance level.

Avira is priced competitively, too. Avira Antivirus Premium 2013 retails for $29.99, while Avira Internet Security 2013 goes for $59.99. A new Plus version of AIS costs a bit more at $69.99, and offers non-security system performance improvements for the extra ten bucks.

A full CNET review of Avira 2013 will be published soon.