It’s Hump Day here in the Windy City, and, as always, we’re reading up on all things digital marketing. Here’s a quick look at what’s grabbed our attention today:

If you haven’t already heard, the release of iOS6 for Mac products will be missing a very important app – YouTube. Don’t fret, just because your phone or tablet won’t automatically include the app doesn’t mean that you won’t have access to it. Google announced last week that the new and improved YouTube app will be available through the App Store. Phew!

Facebook took a step outside of its usual ad placements today by testing its own mobile ad network, which allows advertisers to place ads on other apps or websites based on your Facebook data. This isn’t the first time that Facebook has stepped outside of its own platform to place ads in front of Facebook users’ faces and will likely be just the beginning of their ever-expanding ad offerings, as they look for new ways to generate revenue without disrupting the user experience.

Also this week, Amazon announced the Amazon Maps API, causing many to speculate whether this meant that they, much like Apple, would be kicking Google Maps to the curb. Amazon hasn’t officially said either way, but considering they’re working on their own mapping technology, we imagine it’s only a matter of time.

Twitter has a mobile-first strategy, and yesterday was the launch of several updates that take advantage of the iPad display. You can update your own profile now, adding a big image. Will we see the same kind of creativity we’ve seen with Facebook cover photos? Early indications say “yes.” If you’re having trouble coming up with a big image that fuly expresses your degree of awesomeness, check out these “big image” tips from Mashable.

And because who doesn’t love a good bit of smacktalk on a Wednesday morning, check out what Twitter CEO Dick Costolo had to say about Apple and Facebook:

Twitter CEO Dick Costolo, fresh from a day of smartphone Twitter app releases, said Tuesday night that his company saw Apple as a “mentor” to Twitter.

“Apple is in many ways a mentor company for us,” Costolo told PBS interviewer Charlie Rose. He said the companies had “a great relationship.” Facebook, by contrast, got this chilly description: “We’re very different companies.”

Facebook was pursuing symmetric networks, Costolo said, but Twitter saw the world as asymmetric. They were fundamentally opposed, and competed for ad dollars.

Buuuuurn. Our guess is we won’t see Costolo in a hoodie any time soon.

Have a great Wednesday!