Odd behavior in notifications from Google's hub!

[Waleed]

I'm testing out Google hub by subscribing to the TechCrunch feed,
which does list "pubsubhubbub.appspot.com" as it's hub. I'm seeing
something odd about the notifications I'm getting. There are missing
articles, and a couple old articles are being sent again and again.
Here is a list of the notifications I received listing the post titles
in each one:


11-12 04:38PM: (first notification from the hub)
title = "Facebook VP Leaves A Lover Letter For Apple",
title = "Incsub Launches WP Plugins; App Store For WordPress
Plugins",
title = "Reddit Opens Its Homepage To Anyone Willing To Pay
(Invites)",

11-12 04:44PM:
title = "Myxer Delivers 10 Million Ringtones To iPhone Users",
title = "Incsub Launches WP Plugins; App Store For WordPress
Plugins",
title = "Reddit Opens Its Homepage To Anyone Willing To Pay
(Invites)",

11-12 04:54PM:
title = "Facebook VP Leaves A Love Letter For Apple",
title = "Incsub Launches WP Plugins; App Store For WordPress
Plugins",
title = "Reddit Opens Its Homepage To Anyone Willing To Pay
(Invites)",

11-12 05:01PM:
title = "Incsub Launches WP Plugins; App Store For WordPress
Plugins",
title = "Reddit Opens Its Homepage To Anyone Willing To Pay
(Invites)",


In comparison, here is the list of titles as I see them when I view
the feed at (http://feeds.feedburner.com/TechCrunch)

Facebook VP Leaves A Love Letter For Apple
The ScamVille Lawsuit: Facebook, MySpace, Zynga And More Face Possible
Class Action Suit
Should Nintendo Fear The Apple Juggernaut?
Pingdom Says People Are Tweeting 27 Million Times A Day
Google Announces Acquisition of Gizmo5. They Now Have A Soft Phone For
Google Voice
Forbes Media Acquires Digital Photo Magazine FlipGloss
Flickr Outsources Printing To Snapfish
First Rule Of Facebook Connect: You Do Talk About Fight Club
MySpace Hires Some Social Smarts From LinkedIn
For Charity: Foursquare Looking For Leaderboard Sponsors
Crazy ComScore Charts: LinkedIn Shoots Up Past Twitter
Vitamin D Turns Your Webcam Into A Virtual Doorman
SPDY Gonzales: Google Continues Its Push To Take The Web To Breakneck
Speeds
Trouble At Twitter: U.S. Visitors Down 8 Percent In October
Twitter, Facebook Come To Xbox 360 On Nov. 17
Video: Hands-on With the Chumby One
YouTube Succumbs To Branding As Warner Music Begins Its Return
No Need To Wrap Your Blog Post In A Tweet, Just Sync It With MySpace
That $1.25 Billion Settlement With AMD? It’s About 12 Days Of Revenue
For Intel.
Google Wave Declutters The Inbox With Following Feature
Video: Fox News Takes On Violent Video Games. Again.
Cleaning House Before Its IPO Will Cost AOL $200 Million And Up To
1,000 Jobs
Reddit Opens Its Homepage To Anyone Willing To Pay (Invites)
Incsub Launches WP Plugins; App Store For WordPress Plugins
SpotiChart Picks Up Spotify Tweets, Charts Music Trends On The Fly



You'll notice that the hub keeps sending two of the old posts with
every notification, while skipping some of the new posts. Am I doing
something wrong?

Thanks,
Waleed

[Ravi Pinjala]

Most likely this is the same issue I ran into a few weeks ago. First,
PubSubHubbub only sends the changes to a feed, not the whole feed, so
you would only see a few updates at a time. Second, the hub is sensitive
to even small changes such as the number of comments on a story if the
feed contains that information, so it may seem like it's giving a lot of
duplicate updates for a few items.

--Ravi

[Jeff Lindsay]

Perhaps it's not fair to say the *hub* is sensitive to small changes, but that some publishers may be more update-happy than others.

--
Jeff Lindsay
http://webhooks.org -- Make the web more programmable
http://shdh.org -- A party for hackers and thinkers
http://tigdb.com -- Discover indie games
http://progrium.com -- More interesting things

[Waleed Abdulla]

Thanks Ravi and Jeff for pointing me in the right direction. I did find the cause of the issue, and it turned out to be an advertisement that TC puts at the end of each post and it rotates between two messages. It's probably (and I'm guessing here) inserted using a Wordpress plugin that updates the content of the post periodically. 

It would be nice to be able to filter those updates out, but they look exactly like content updates (because they are), and therefore will create unnecessary load. Oh, well.

[Jeff Lindsay]

Sounds like something the hub can do: make sure not to send the exact same data more than once.