Witnesses don't have to run a seed node. Seed nodes are what other nodes sync from and supporting witnesses(and non witnesses, nothing preventing anyone from running one) who run them.
I run multiple seed nodes(2 right now, was 3 in the past and it'll be 3 again soon).
Can any computer run that, and what are the incentives and benefits to hive for running them?
For seed nodes: The benefit to hive is that when other nodes are syncing, they can get data from them. You just need a computer with a stable connection(my nodes are hosted in datacenters with a provider who has multiple connections to the internet) and a IPv4 address(I've created a issue for adding IPv6 support to nodes but sadly no developer has taken it up https://gitlab.syncad.com/hive/hive/-/issues/381 maybe someone will soon poke @howo) or some sort of way for others to reach it(if you want to run it at home, and your provider doesn't use CGNAT, you can use port forwarding). My server running the node is pretty powerful, but it any modern computer with at least 16G of ram can handle this. You'll also want 1TB of fast storage(NVME), though we are only using about 550 GB right now.
There's not direct incentive to running a seed node. You don't get paid paid for running one. But if you are a witness, it might be a reason that others vote for you since you are helping keep the platform running.
For a witness node, requirements are mostly the same. It's recommended to keep the full history, but you can use the config option that lets you store less of the history(though you shouldn't as a witness unless you know what you are doing). You really want a stable server here since the witness nodes are the ones producing the blocks. There is a direct incentive since you get paid some HP per block that you produce.
This post from @gtg is a good one for getting your first node setup.
Wow, how you took your time to explain everything to me is details. I can't thank you enough. I'm not so old around here, but I'm willing to stick for long and build some stake. Over the years I will put this into practice and become a witness.
I am also a witness so a vote helps 😀. If all goes well, Hive should have a seed node in NYC again by EOY.