To each his own. I only jot down a name, a book title, a website, a date or two out of a great lecture. Then I can pursue these leads after the conference. What do I do with all the time I save in the lecture by not following your note taking regimen? I have more time to examine the ready-made notes and AV displays provided by the lecturer and, most preciously, time to think over and "chew" the ideas presented.
Can I leave the lecture hall with as much detailed record of the lecture as Phil can with his copious notes? No. But I do order the Full Monty of CDs from the recorded lectures. I can listen to these in my car throughout the year, giving me the advantage of more detail than Phil's notes can give him, combined with a ready made venue which would not otherwise be exploited for intellectual gains.
When I teach software to engineers, scientists, and other technical people, I always get a few who are like you in that they are big on note-taking. When I see them sitting down and deploying their various notepads, electronic gadgets, etc., I say whoa, there! OK, we are going to go through this material three times.
The first time, I am going to demo it and explain what it does and what its principles of operation are. You are free to stop me at any time and ask questions. I will answer any question, but there will be no note-taking. The student's focus is on the screen, the data presented on the screen, and on my hands and voice, so that they are engaged as much as possible with what is happening, why, and the metaphors used to present the data and the user interface.
The second time, the student is going to be in the driver's seat, with me observing, answering questions, and guiding him out of blind alleys. He will try to repeat the operations he saw me perform earlier, stopping to ask questions on any point that confuses him. Again the focus is on the screen and what is going on in the computer and no notes are allowed.
The third time is a repeat of the second time, except that the student can take notes, and now has a better grasp of what the system and its interface are all about. So he can ask better questions and get good notes that will help him think it through later.
But, crucially, the notes were not distracting him from the screen and from my verbal explanations of what it all means during the critical period when he was first learning the basic concepts.
Maybe the bandwidth is a lot less in a many-to-one lecture format vs. a hands-on technical tutorial session, leaving otherwise idle hands with time to take notes.