I think it's very unlikely that the company would go after you for revenues from your blog and at the same time another company could go after you even if there

I think it's very unlikely that the company would go after you for revenues from your blog and at the same time another company could go after you even if there was no IP clause in the contract because they would argue that an implied contract existed or whatever other reason they chose. The papers you signed mean something but they are in the context of other laws and legal precedence. I don't stop thinking about work when I'm at home or it's after 5pm. If the solution for a bug comes to my mind in the middle of the night I'm not going to sell it back to the company because I own it. Like it or not, the kind of job we do is like that. I think the key is to ensure that your compensation is adequate for this expectation. Similar IP clauses are part of standard contracts for almost every company in almost any geography. In some ways they protect you as well because they help ensure your coworker doesn't steal company secrets. Companies going after employees for random side projects or blogs is almost unheard of (I've never heard of it) even though pretty much every employee signs similar contracts. A standard contract probably also says something about it being subject to change and about needing to follow other company policies. So even if there was no explicit IP clause it could be hidden in some company policy. EDIT: I doubt the hiring manager meant that you can't play the guitar or engage in any other creative activity in general. But OTOH I don't think it's unreasonable to expect an employee not to engage in activities that would negatively impact his job performance. E.g. not to hold two full time dev positions concurrently in two companies and similarly not to have a full time, or something approaching full time, side project. If you burn out because you're trying to work on a side project while having a "full time" dev job that's really not playing by the spirit of the employment contract.