So, something I've never heard of is now free ... do I give a shit or not?
If you've never heard of it, and can't be bothered to click a link placed directly in fron of you, then no, you obviously don't give a shit.
Hey, why not just post URLs with no summary, and we'll cut out the middle man entirely?
Counter-point: if you can't be bothered to click a link, why not just repost the full article, then?
The people who are interested in this piece of news already know what Xamarin is, seeing as it's pretty popular amongst cross-platform mobile developers, so it's no more unreasonable to not include a description than it would be to not describe what Android or iOS is. Anyone curious who doesn't already know what it is just has to click the link to find out, and if they can't be bothered to do that, then they just don't want to know.