Background on 999 errors

From PluginWiki

This article is based on information provided by Gordon Strause of Yahoo.

Why are there 999 errors at all?

The 999 errors are caused by a Yahoo! system that is designed to prevent automated use of Yahoo! Groups. Generally automated use means one of four things (all of which are bad). In increasing order of badness, they are:

• auto responders
• viruses run amok
• denial of service attacks
• spam attacks.

The spam problem is the one Yahoo are most concerned about. Yahoo! Groups has been always been under attack from spammers, but especially since around Sprin 2009, they are beating the CAPTCHA mechanism (those funny characters you have to type to verify account creation) well enough to:

• create tens and hundreds of thousands of accounts and groups
• add millions of users to these groups
• send out tens or even hundreds of millions of spam messages a day through Groups.

This is unacceptable for all sorts of reasons, not least of which is the fact that these attacks damage the normal use of Groups, and is responsible for some (though not all) of the more visible problems with Groups' reliability.

Since Spring 2009, Yahoo have taken a number of further steps to combat the spam problem, one of which is (unfortunately for us) tightening the limits that cause the 999 errors. This does mean that some legitimate users, especially plugin users, are being hit by 999s.

How do 999 errors work?

Here are some characteristics of the way they work.

• Different pages within Groups have different limits (and there are overall limits)
• They are based on users not groups (meaning that if you moderate multiple groups, you're more likely to hit the limits since you're hitting double (or triple or quadruple, etc.) the number of pages.
• But "users" means IP addresses, and not Yahoo! IDs. So logging in as different users won't help you achieve higher limits. On the other hand, being able to use a different IP address will reset you.
• The IP address nature of the limits also means that if you share an IP address with other users who are using Yahoo! Groups, your limits will be lower since their use will count toward your limits (and your use will count toward theirs).