The Windows Live Mail Desktop team have a blog post entitled Better Together with Active Search where they talk about a new feature currently being called "Active Search". The post is excerpted below

Much of what you need to get done online – from planning your next vacation to remembering to buy flowers for your mom on her birthday – is piling up in your inbox, just waiting for you to take action, usually by looking something up on the web.

With this in mind, we’ve designed Active Search to make it easier for you to act on anything that piques your interest while reading your email.That’s why we show you key search terms we find in a message and provide a search box right underneath, so you can quickly search for terms of your own.

We also show search results and sponsored links right inline, so you can see what’s related to your message on the web, without having to open a new browser window. Of course, if you come across something really interesting, just click More results… and we’ll open a new window with a full set of search results for you to dive into.

Because we only look for relevant keywords in the current email message or RSS article you happen to be viewing in your inbox, there are times when we just can’t find anything relevant enough to show you. So we don’t – we just show a search box ready for you to enter search terms you happen to come up with while reading the message.

I got a demo of this feature from Bubba in the cafeteria a few weeks ago and it seemed pretty interesting. It reminds me of text ads in GMail but for a desktop application and a few other key differences. What I'd love to know is whether there is a plan to make some of this stuff available as APIs for non-Windows Live applications. I wouldn't mind being able to integrate search ads into RSS Bandit to offset some of our hosting costs.