[retonato]

Don't underestimate possible legal problems. Tech people tend to simply throw them aside ("I will use a VPN/Cloudflare/Onion, no one will find me"), but here are my 5 cents:

1. Most likely - you site will not gain any significant popularity and you will decide to close it on your own. Meanwhile you will just be getting some automated DMCA emails/complaints from time to time, that's it.

2. Less likely - you site will be somewhat popular, it will become an attractive target for copyright owners and law firms (not as attractive as thepiratebay, but still). It usually takes just a month or two for some interested law enforcement agency to find out who you are (forget about all privacy protection methods you know, it is very easy to slip and eventually you will slip; you need to be lucky every time, they need to be lucky just once). Depending on what country you live, you will end up with a few thousand dollar fine (best case) or tens/hundreds of thousands + a small jail sentence + a criminal record. Not bad for a hobby torrent site with no income and a minimal community, is it?

Just to reiterate this one more time - it is VERY easy to find out who you are for any interested government agency [in your country], most of those 1-2 months will be spent waiting for replies for their letters and other similar bureaucracy, not for some CSI stuff.

Here is how it might go. First they will check the site domain and IP address and ask your hosting/domain providers to reveal you payment details (name/address on credit card). That's enough in 95% of all cases. Even if you use Cloudflare to hide your site IP and even if you use bitcoins to pay for everything - that will help only for some time, eventually Cloudflare will reveal your server IP and bitcoin transaction will be tracked back to your credit card. That's just a question of time and whether you are "wanted" enough or not.

[retonato]

If despite all this you still decide to go forward - don't forget to import all the available torrent data on the internet (there are tens of dumps here and there), that way you will have MUCH larger database, than just by DHT scraping alone. This is a good place to start: https://archive.org/details/torrent_metadata_archive_sample

Creators of such sites (including me) tend to focus too much on the number of torrents, no matter if they are active or dead. Regular users are interested mainly in active torrents.

Plus they want to see the current number of seeders/leechers, which is very difficult to keep up-to-date for a large database.

Plus they want to see a torrent creation/upload date, which you cannot get from DHT (you can record the day you found a torrent, but it will work only for newer torrents, not for historical ones).

[retonato]

Of course, you can just provide a code for users to run on their own computers, but don't expect that anyone will really use it (maybe just a few people here and there, I really mean it). Everyone, who is really hardcore enough to run something on their computers to obtain torrents will just use Jackett (https://github.com/Jackett/Jackett). It can search through the huge number of torrents, which no local DHT scraping/search engine can provide.