Last night, Google announced on the Google Webmaster Center blog that they are removing three features from Google Webmaster Tools as part of their "spring cleaning efforts." They include:
Site Performance
This is a feature I like to use, where I can check the historical changes to how the site speed is over time. Google introduced this feature back in 2009 and it has been plagued with issues since it has launched. Google said it is being "removed due to low usage." There are of course other tools you can use, including site speed in Analytics and others.
Robots.txt Tool
A tool I don't think I ever used, and Google said it had "very low usage" and they are removing it. Google said most sites do not even need a robots.txt file, and if they do, you can use a text editor to make one.
Subscriber stats
Google is removing this report as well. It was introduced when they acquired Feedburner and wanted to bring in additional reports into Google Webmaster Tools. Truth is, it is rarely used as well and RSS readers is somewhat dying as well.
Forum discussion at Google Webmaster Help.