content: I can only speak about Yacy. It's a decentralized search engine. Incredibly interesting proof of concept but it needs a better way to rank results in terms of usefulness/popularity. Currently the experience is like searching the web with Windows's finder or some equally shitty tool. You can try it here: http://search.yacy.net/ Needless to say, if you use Yacy through that URL you're not contributing to making the network more resilient. In order to do that you need to install the Yacy software and start indexing some websites and keep the software open as much as possible so it can get accessed by the rest of the peers. If you're unfamiliar with decentralized networks the idea is there's no single point of failure. All computers interacting are equally  important. If one goes down your requests go through a different computer (or sets of computers). It's where we're trying to go in many areas (Bitcoin, etc.) but doing it right is difficult as fuck. The thing with these decentralized networks is they're very difficult to properly monetize. It would help loads if people started donating or contributing code for these projects. Briefly about the others: Grub:  Last Update: 2013-04-03  I'd say it's dead, Jim. Seeks:  Latest commit on Apr 28, 2014  Dead as well. Even though the last Yacy version is from 2016 the guy is still contributing code to it so it's taking him time to improve it but it's not at all abandoned. Luckily. I agree with your assessment about Silicon Valley.