Learn English – What does “scratching the proverbial itch” mean

In the context of a conference, a track is a series of related presentations all focused on the same topic.

For example, if you look at the conference planner for OOPSLA 2014, you'll see that they had four presentations on Program Analysis and the Web in one room, while there were four more talks on Runtime Systems in another room.

So, two conference attendees might be having lunch together, and say:

"Did you see that talk on garbage collection?"
"No, I was in the other track."

meaning that she was listening to the talk in the other room.

Evidently, the author of the book started the C++ track at the Software Development Conference, and later did the same thing with the Java track. The chair of a track often has the responsibility of introducing each speaker during that session, and making sure speakers don't go past their allotted time.

Incidentally, a corollary of Murphy's Law says: At a conference, the two talks you most want to attend will be held at the same time.

Anyone who has had a rash or mosquito bite knows what it's like to have a strong urge to scratch it. Even when you're told that scratching it will only make it worse (such as with a scabbing wound), it can still be hard to keep your fingernails away.

The word itch, though, can refer to a figurative itch as well as a literal one. The word itch can be defined in several ways, but a few notable ones include:

• (n.) An irritating skin sensation causing a desire to scratch
• (n.) A restless desire or craving for something: an itch to travel
• (n.) An uneasy longing or propensity; a teasing or tingling desire: an itch for praise
• (v.) To have a persistent, restless craving.

The words itching and scratching often go hand-in-hand. For example, a musician might have a sudden itch to play some music; sitting down at the piano or picking up a guitar could "scratch that itch" by soothing or fulfilling the desire.

In the case of a cognitive itch – the phrase used in your article – that would be a figurative itch inside the mind. The author is suggesting that the person with the earworm has a strong urge to hear the song (or at least play it in their mind). Succumbing to that itch and "scratching it" (in the case of the earworm, that would mean singing or humming the song) would bring it back to the forefront of your mind, which gives to the desire to hear it again, thus producing a vicious cycle and keeping the earworm stuck in place.