Does posting my work on the Internet protect me if someone else tries to publish it with peer review under their own name?
There are sites like arxiv.org where you can publish something, which isn't peer-reviewed yet, but which becomes public and stakes a claim to the idea.

However, that's usually what some people (usually at universities, not companies) do when they have a full-fledged paper to release. In your case it sounds, if I read this correctly, like you have some general ideas you have not yet had a chance to pursue in depth.  You're considering putting them out and inviting others to run with them, but want some credit.  I would say that if you simply put out a general idea, that is worth an acknowledgment in a paper, not co-authorship.  Being an author means actually doing some of the work -- writing text, doing experiments, etc.  I don't think what you describe rises to that level.  

One thing you might consider doing is putting out enough information to tease people into inquiring for more information, then trying to work with anyone who inquires to be more directly involved in the work as it proceeds.