Google's "ReCAPTCHA" API-based user validation process is very popular. So popular, that internet users are running into warnings here and there on the web, suggesting that it's about to stop working on some websites.
The reason? The V1 version is deprecated and about to be retired. It's going to stop working at the end of March, in just a couple of weeks from now.
The problem? Lots of sites have yet to update from V1 to V2. What happens to those sites on March 31st? I'm not sure, but it probably won't be a good thing.
What's the connection to email? Why am I posting about this?
Because Cloudmark is running V1 of the ReCAPTCHA. The spamrl.com spam filtering service is running the old version, too. The SURBL blacklist's lookup page, too. (Though SURBL just fixed theirs.)
There's probably a lot of other sites out there running the old version of ReCAPTCHA, as well. Do you use ReCAPTCHA on any of your websites? Have you upgraded to the latest version? If not, the time to do so is NOW.