Vodafone Group plc (NYSE: VOD) is out on a spending spree at the moment, as it's splashed out €505.5 million ($784 million) to acquire mobile social networking company ZYB Technologies ApS and full ownership of German fixed-line operator Arcor AG & Co. KG .

The acquisitions boost two strategic areas for the world’s largest operator by revenue: fixed broadband services and mobile Internet applications.

In Germany, Vodafone today announced that it bought the remaining 26.4 percent stake in Arcor that it didn’t already own for €474 million ($735 million) in cash from Deutsche Bahn AG and Deutsche Bank AG. Full ownership of the German fixed-line operator will give Vodafone greater control over the business and allow it to integrate the fixed broadband services with Vodafone Germany ’s mobile services. Arcor has 14 percent of the German DSL market with 2.6 million DSL lines. (See VOD Acquires Arcor.)

Vodafone has been on a mission to add fixed broadband services to its portfolio and now can offer these services along with mobile offerings in thirteen markets. Today’s deal with Arcor follows Vodafone’s acquisition of Tele2 AB (Nasdaq: TLTO)’s fixed broadband operations in Italy and Spain for €775 million ($1.2 million) in October last year. (See VOD Gets Fixed in Italy & Spain, Vodafone Buys Tele2 Units, and Vodafone Unveils Convergence Plans.)

Separately, Vodafone got in on the Web 2.0 game last week with the acquisition of ZYB for €31.5 million ($49 million). The Danish company has a social networking and online management tool that lets users back up and share their mobile handsets' contact and calendar information on their PCs.

As Pieter Knook, Internet services director for Vodafone Group, puts it, “This is Web 2.0 in action.”

So, that’s gotta be good.

ZYB will remain in Denmark and be integrated into Vodafone’s Internet Services Division.

— Michelle Donegan, European Editor, Unstrung