I’m bouncing a little bit from session to session this morning.  I made the mistake of ducking into a couple of the “Products & Services” sessions during the 9am slot.  Those where just thinly veiled sales pitches.  I ditched each one after ~10 minutes.

I’m finding the usability sessions the most interesting.  I caught the end of “The New Hybrid Designer” session and that sounded interesting, but couldn’t get much out of it yet. I stayed for “Designing for and with community” which shared good lessons from Mozilla Corp’s work in managing design feedback from the community.  I’d rather hear about designing apps/sites to foster and generate community, but it was intellectually interesting nonetheless.

BTW, I noticed in the conference program addendum that they do have a solution to the power problem: they’ve arranged to have a Web 2.0 Expo Power Room where you can plug in your laptop, but with no security you can’t leave it there.  Oh, happy day.  Someone call the pope and let’s get someone canonized.

I haven’t been too a big conference in a while, and it is pretty exciting. And the Moscone Center is a beautiful venue.  And the weather was beautiful in SF today; the massive windows in Moscone West made me want to be outside instead…

But Zoli Erdos has it down: registration was a disaster this morning and ummm… what about the power?!?  I can almost understand not having power strips along the rows in the session rooms (though I’ve been to conferences that have had it).  But there also isn’t any juice at the tables outside of the session rooms.  That’s ridiculous.  I bonded with some guys outside one of the session rooms as we huddled around 4 outlets in one corner.  Hopefully, they’ll fix it for tomorrow.

The best thing in Day 1 was definitely Yahoo’s presentation on high performance webpages.  Very informative.

Next up for me: Web 2.0 as a UI Paradigm.  It’s starting very slowly; the speaker is just running down the common UI features of Web 2.0 apps/sites, and the pros and cons of DHTML/JS/Flash/Java/etc.  Not interesting at all. 

Per speaker, Rich Internet Applications tends to mean:

1. Customizable interface
2. Things download in chunks for perceived increase in performance
3. Instant feedback, minimize reloads
4. Tons of HTML and JS
5. Not crawlable by search engines
6. No standard UI components yet
7. No standard solution to “Back Button” problem

So here’s the first interesting point: with Web 2.0, the focus of UI is on tasks, not items.  So task-focused UIs “let you perform ancillary or housekeeping tasks without taking focus away from your core task”.  E.g., logging in/out is not a core task, it’s a necessary evil.  Other non-core tasks might include: changing account settings, spell check, reorder items, flagging items, etc.  All non-core tasks should not cause major changes to the UI (no full reloads, etc.).  Makes sense to me…

An example is lala.com when you add a song to your list.  Another: Trulia.com.  Signup is in a DHTML popup; the page you were on doesn’t change or disappear at all.  Reddit’s login box.  Trulia.com, adding a neighborhood to a comparison.

Examples to the contrary: Amazon, refresh this page link.  Reddit,  login page.  Yahoo! Answers, ask a question and it dumps you to login screen.

Luckily for me in this one, I found a power outlet in the session room!  I shared it with a fellow attendee and we basked in the glory of our flowing electrons.  Ahhh…

I’m attending the Web 2.0 Expo at the Moscone Center in SF this week.  First up is the High Performance Webpages workshop, presented by the Yahoo! Exceptionial Performance team.  Pretty interesting so far.

Their primary thesis is that 80-90% of user-perceived response time is client-side and images; only 5-10% is the actual generation and downloading of HTML.  Even if the user has cached a lot (they’re visitng the page again), the percentages don’t change much.

Some of the interesting facts they’re citing:

• The percentages cited above (HTML-generation vs. other things in user-perceived response time) is pretty consistent across the 10 biggest properties on the web.
• 40-60% of unique users visit with Yahoo with an empty cache. ~20% of total page views are with an empty cache; higher than you’d think.
• Base cookie sizes for some major web properties set at their splash page (in bytes):
  • Amazon  60
  • Google  72
  • Yahoo  122
  • CNN  184
  • YouTube  218
  • MSN  268
  • eBay  331
  • MySpace  500
• Use at least 2 but no more than 4 aliases (hostnames) for images from a single HTML page because the browser will download 2 objects in parallel per alias.  More aliases leads to CPU thrashing and more DNS lookups.
• 14 Rules (in rough priority order):
  1. Make fewer HTTP requests
     • Use image maps to reduce # of images.
     • Use CSS sprites; <span style=”background-image: …; background-position: -100px -100px;”>.
     • Use inline images, but not supported in IE; binary of image is in HTML! (The binary is in the HTML?!? Oh my god, that hurts my sensibilities!)
  2. Use a CDN (like Akamai; not practical for small sites)
  3. Add an Expires header (set it far in the future)
  4. Gzip components (not just html files but all non-binary ones of a non-trivial size)
  5. Put CSS at the top
     • Where you’re supposed to, because pages don’t layout until all the .css files are downloaded.
  6. Move JS to the bottom
     • Not where you expect to put it.  Put it as late as possible in the code because downloading .js files block the browsers from parallel downloading of other assets (like images).
  7. Avoid CSS expressions (ones that are calculated off other things; way too much processing)
  8. Make JS and CSS external (this makes it cacheable)
  9. Reduce DNS lookups
  10. Minify JS (“minify” is a word? Huh, I guess it is.  In dev-talk, it means to remove unnecessary whitespace.)
  11. Avoid redirects
  12. Remove duplicate scripts
  13. Turn off ETags
      • Entity tags prevent caching by the browser because ETags are never the same for the same asset across different servers, so for a multi-server farm, it does a lot of harm.
  14. Make AJAX cacheable and small

Update: They posted the presentation; it’s been the best session so far, IMHO.