Here’s our roundup of the of the week’s tech business news. (It’s shorter than usual, owing to the fact that there’s less going on during the holidays.) First, here are the most popular stories VentureBeat published in the last seven days:

skypeSkype outage affects tens of millions — Skype suffered a widespread and lengthy outage Wednesday with its Internet calling service.

Microsoft says “Not!” to Kinect sex game — Microsoft got excited when hackers started coming up with novel uses for its Kinect motion control system. But it was less than thrilled with the idea of using Kinect for sex games.

How mobile apps are spying on us — Your favorite mobile apps could be collecting and transmitting your personal information, including your name, contacts, location and even your phone’s unique ID number, to ad networks and other third parties.

The best and worst in mobile 2010: It’s all about Apple and Android — We look back at the year in mobile news.

And here are four more posts we think are important, thought-provoking, fun, or all of the above:

warning birdsHow Twitter acquires people — When is an acquisition not an acquisition? When Twitter’s involved, apparently.

When Tesla’s lockup expires Monday, will its stock drop? Short sellers think so — Tesla’s IPO has been one a few super-successful cleantech public offerings this year, if not the most successful. But will the good news continue after the 180-day post-IPO lockup period expires Monday and new shares flood the market?

Foursquare, Gowalla, Instagram: Mobile photos are everywhere — It’s been a big week for numbers about photos.

Salesforce nabs another Y Combinator startup in email contact manager Etacts — Salesforce announced Tuesday that it has acquired email contact manager Etacts for an undisclosed sum.

[top image via ReadWriteWeb]