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The author

Epiphany Search

YaCy (‘ya-si’) is a new concept in searching - a decentralised search engine model. Similar existing P2P networks operate – each node (i.e. user) who uses the software will contribute to the overall functionality of the search engine.

The Pros

1. Free Internal Search YaCy can easily be used to quickly set up a free, private, internal search engine by individuals or companies. This offers a substantial cost saving on existing ‘private search’ providers that are currently used by many companies and organisations. 2. Fault Tolerance & Scalability By using a distributed P2P model, there is an extremely high level of fault tolerance. Machines can join/leave the network without killing the actual search service. Although many large search engines such as Google have decentralised server farms and high levels of fault tolerance, the entity itself – the organisation – is still a centralised entity that can be affected by various forces (market trends, financial issues, etc). 3. Your Search Portal Is Local To use YaCy, you install the software and run searches from your local machine. You’re not forced to go to a single web-portal, such as or This means that if you can’t access or Yahoo – you can still use YaCy. 4. Potential Immense Computing Power P2P networks have access to an immense amount of computing power – many hands make light work. This is why projects such as [email protected] and [email protected] work on a distributed processing model. Leveraging this computing power could allow YaCy to go one step further than existing search engines, allowing it to process even more complex collections of search data. Although Google has the most dedicated servers of any known company, there is a massive cost with buying and running all these servers. In effect, many search engines are in a ‘server arms race’ – which is costly. Whoever has the most computing power can offer the fastest services and process their search data faster too. 5. It’s Free. No Ads. YaCy is free and there are (currently) no advertisements. This is because YaCy doesn’t really have any hardware or running costs to cover.

The Cons

1. Installation Required You have to install the YaCy software to use it. This is probably the biggest downfall of YaCy. There is a demo search portal, but it’s exactly that – only a demo. Many users will shy away from having to install more software – especially when users will say ''Google already works and I don’t need to install anything to use that''. I’m sure many users would happily download YaCy and ‘get involved’ by joining a wider public search network but they’ll want to give it a road test first. This will require a fully functioning web portal because the existing demo doesn't return ‘decent’ search results for most queries, which won’t endear users to YaCy as there’s “enough” search engines out there already. 2. It Runs Locally Although the YaCy site outlines “it is not possible for anyone to censor the content of the shared index”, people will start to question whether search indexes and results can be ‘modified’ by those with ill intent. YaCy stores index data in distributed fragments but it could still be possible to alter the index data if you have access to enough fragment instances. One potential scenario could be the use of a large bot-net, with all members using YaCy – possibly enough to piece together complete specific sections of a search index – enough to then doctor the fragments to favour specific sites or search terms. Although it’s a highly unlikely scenario, if data is being stored on local machines, there are plenty of enterprising individuals who will most likely give it a try. Even if it’s simply because some people may see YaCy statement that it is “not possible” for anyone to censor the shared index as a challenge. 3. Paranoia People will start worrying about their search queries being sent to ‘other peoples machines’. Even though the YaCy site clearly explains that queries are never stored – some people will always question this statement – just as they do with major search engines. 4. ISPs Although YaCy appears to use relatively little bandwidth when compared to users accessing services such as YouTube, I can’t think of many issues that YaCy would cause for ISPs. However, many ISPs have a clause in their contract for home users stating that you cannot run a ‘server’ that uses their services if you’re a home user. This could potentially include YaCy – as a P2P network is exactly that – a collection of interlinked ‘servers’ that process requests.


YaCy really is a piece of amazing software, which is well engineered and overall is a fantastic solution that is working in the real world. I think that the future of YaCy lies in use by private companies, governments, etc – rather than the general public. This is simply because the vast majority of users ‘already use Google/Bing/Yahoo’ and they need to actively install YaCy before they can use it – which will put most users off. Would your company benefit from YaCy or how would you use YaCy at your company? Please leave our comments below!