One of the tips says "Research can be hazardous to your villagers". What does this mean?

It means that your researchers will suffer injuries while working and those injuries will weaken them. Builders can suffer similar injuries.

but how can researching hurt anyone?

Maybe they're blowing things up! Haha!

Researchers get hurt all the time. Madame Curie suffered serious injury in her work with X-rays. These villagers don't work with X-rays, but their research is hazardous, too.

that would be cool if they blew up the research table!!!!but the builders would have to build it up again!

what id like to see is the researchers invent a boat... or a ladder that goes up the cliff beside the waterfall... the two villages could trade... village one could trade tech for new clothes and village two could trade collectibles for food etc. is there any possibility about some day integrating all of the vv games into one?