Who's tracking you on the web? Find out with Collusion.

There is a new add-on for your Firefox browser called Collusion. I just downloaded it and installed in on my computer.  Collusion generates a network diagram of the website you visit and other sites from that one.  All of them collect information about you and share that information. Collusion a way to see who is tracking you.

Here's a snippet from my visit to Contentions, a political blog.

You can see the blog itself in the center.  What I didn't know, but now I do, is that Contentions shares my visit to them with 23 (count 'em!) other sites. Whoa! That's a lot of sites that know about me that I don't necessary want to having anything to do with them.  Some of these sites may be innocuous, but some are tracking me to use that information to make money or generate ads.  With the Collusions diagram on a tabbed page (you simply click on the Collusions icon on your Firefox toolbar at the bottom of the window) you can put your mouse over any node to see what the node is. Also, Collusion gives you information on

It's not clear to me what to do about this, but the first step is to know that there's a problem. Collusion is showing us the problem.

Here's some of what Collusion reports on my visit to Contentions (with a cut and paste just below):

"When you visit commentarymagazine.com, it informs the following websites about you.

• google.com
• doubleclick.net
• addthis.com
• turn.com
• afy11.net
• openx.net
• wtp101.com
• revsci.net
• adnxs.com
• yieldmanager.com
• quantserve.com
• mathtag.com
• invitemedia.com
• jewishideasdaily.com
• contextweb.com
• scorecardresearch.com
• nrelate.com
• rfihub.com
• vizu.com
• advertising.com
• pointroll.com
• gwallet.com
• serving-sys.com"

Some of these sites I know about, and some I don't know about. But for all of them, I had no intention of telling them about myself. Yet, with a click to one site, these others know about me. That's scary.

Courses for Everyone

What do Stanford University, Princeton University, University of Pennsylvania, and University of Michigan have in common?

For one thing, these top tier schools now offer courses on-line and for free. If you haven't seen this before, click on the link and take a look at what's available. There are humanities, computer science, health care, and economics courses, to name a few subject areas.

I took the cryptography course taught by Dr. Dan Boneh and it was excellent. The course website has the slides for the lectures (pdf format and as a PowerPoint file) available for downloading. The videos can be watched (and saved!) in various formats.  In fact, in one video format, the video will pause so that the student can respond to a question in a box on the screen. The student can press a button to see if his answer is correct or not.  It's a great way to interact with the lecture (limited though it is) and keeps you involved with the material.

After a  week of lectures (usually about 5-hours, maybe less, of viewing time) there is a homework assignment. The homework was mostly multiple choice with a few fill in the blank answers. You can save the assignments as you do them and once you've completed the assignment, you submit it for immediate grading. The homework comes back with your answers graded and with comments about the answers you selected. Thus you learn why you were right (let's say you guessed the answer!) and why you may have been wrong.  The homework was due about a week, I think, after the material end date.  If you submit the homework after the due date, you lose 50% of the points.

At the end of the class there was a 13-question final exam with a two-week time period to complete.

Based on the one class I took, I signed up for three more. The cost is zero but there is a commitment of time and it's not small. Plus, the course goes week after week so there's a commitment of continual participation. Still, you have a chance to learn new topics in your home or office with no travel required.

The course was not as good as a traditional lecture. You can't ask the professor questions and you hear and see the lectures on your own without the benefit of peers nearby. There is a discussion forum and I found that useful to clear up ambiguities in the homework. But that's all I used them for; I think other students probably made greater use of the forums.

I encourage you to take a look at the courses, and if you find one to your liking, sign up. You have nothing to lose and can gain new knowledge in the comfort of your home or wherever you are.

Blogging again

Dear Friends,

It's been a bit since my last post but I'm ready to begin posting again.

My time was committed to other activities over the past few years and I didn't have the opportunity to write here. But that commitment is completed and I have more free time to write. I intend to do just that.

So, come back here soon and look for more posts and interesting tidbits of science and engineering.

David