## What Can You Do With This: YouTube URLs

See the pilot for instructions.

BTW: Give it up for Megan:

1) How many videos can YouTube hold before running out of space in the identifier? Did they plan well? Are they going to run out of space? How fast are videos being added? Do videos ever go away and free up these strings?

2) Are those “v=” strings case-sensitive? How does that change the total possible combinations?

3) What characters does Youtube use in the “v=” string? How does adding one allowed character change the total possible combinations?

I'm Dan and this is my blog. I'm a former high school math teacher and current head of teaching at Desmos. He / him. More here.

1. #### Rhett

March 11, 2009 - 6:26 pm -

Help…must resist….do not analyze…. must instead fix blog.

A couple of those videos are just crying out for a blog post.

2. #### Dan Meyer

March 11, 2009 - 8:30 pm -

Shoot, see, the content of the videos was supposed to be beside the point, which is why I didn’t hyperlink ’em. But, yeah, enjoy ’em in health.

3. #### JYB

March 11, 2009 - 9:23 pm -

I’d have responded earlier but my school web filter blocks youtube. Very helpful. And it blocks your site. Also very helpful. And it blocks my class blog and wiki. At least they were kind enough to block it halfway through the school year without telling us, just as the staff and students were starting to see the potential.

Ok. Done b_tching.

4. #### Megan Golding

March 12, 2009 - 1:27 am -

Looks like YouTube uses 11 characters to identify a video. My students might ask:

1) How many videos can YouTube hold before running out of space in the identifier? Did they plan well? Are they going to run out of space? How fast are videos being added? Do videos ever go away and free up these strings?

2) Are those “v=” strings case-sensitive? How does that change the total possible combinations?

3) What characters does Youtube use in the “v=” string? How does adding one allowed character change the total possible combinations?

And I suspect their questions might follow in that order. Looks like something I could use in a permutations/combinations lesson.

5. #### Kate

March 12, 2009 - 2:50 am -

JYB you sound like me last year. Youtube is still blocked, but we got them to stop blanket blocking blogs. For us it was a matter of finding the right person at the district office to complain to (loudly, frequently, and involving as many complainers as you can muster.)

Also, what Megan said.

6. #### David

March 12, 2009 - 6:02 am -

Anyone notice the first related video for the last link? I bet my students would rather see that one.

7. #### Clint H

March 12, 2009 - 7:14 am -

Following on from @Megan, when will YouTube need to change its naming convention?

8. #### David Cox

March 12, 2009 - 10:19 am -

Has YouTube always named videos this way?
Are there any non-alphanumeric characters other than “_” used?
Will they have to change their naming convention? If so, when?

9. #### Nick

March 12, 2009 - 10:56 am -

Maybe more along the lines of when will you have your next oil change, ask how much does it cost to run youtube? How much does profit does youtube make?

They could use the naming conventions to estimate the number of videos, estimate the average size of a video, determine the amount of storage needed to hold it, estimate the amount of bandwidth used by youtube and the cost and then compare that with the ad revenue for a bazillion users a day.

If I were a kid I’d be unthrilled by counting the number of videos, but inately motivated when you talk about millions of dollars from hosting stupid movies.

10. #### Dan Meyer

March 13, 2009 - 9:06 am -

Right, good stuff. Not terribly challenging, I admit, but I love the idea that some of my students, after this sort of question, would never look at a YouTube URL (or a Twitter status id, or a tinyurl identifier, or or or etc.) the same way ever again.

Wish I could find a graph of total YouTube uploads over time. Fit an exponential model (presumably) to that graph and solve for the total number of permutations.

11. #### Kate

March 13, 2009 - 12:38 pm -

I’ve been disappointed more than once by the “Statistics and Data” tab youtube offers for every video. Pfft. You’d think google could do better than that.

I’ve had success in classes using youtube as a context. I like this video that has had 204 views. What if every viewer got one new person to watch it every day? Interesting conversations – how do they count views, are they unique? are we assuming the people who already watched it watch it again the next day? etc etc.

12. #### John

March 16, 2009 - 8:38 am -

1) Is there some categorization information hidden in those “v=” strings? There is in social security numbers.

for a good problem on social security numbers. (I think you
might have to be a member of NCTM to download the article)

2) What kind for information might youtube want to store in
those “v=” strings? and how would they encrypt it?

Encryption seems to be a topic that most students hook into.