Om this morning broke the news that Skype is looking to raise as much as $100 million in an initial public offering. The SEC filing is full of interesting tidbits including Skype’s $406 million in revenue during the first half of 2010, $344 million in legal expenses to acquire the P2P technology from the firm’s founders, and a $6 million investment in the music startup Rdio. But as Peter Kafka of All Things D points out, perhaps the most interesting nugget is Skype’s “adjusted EBITDA” profit of $115.8 million during the first six months of the year. That accounting concept may seem obscure to some onlookers, but the figure is sure to attract the attention of the investors Skype will need for a successful IPO.