I know there exists already a post, describing nearly the same, but I think mine is a bit different.
What I would like to know is how you organize your extension methods
@Juri- If you think about it this is the same problem as developers knowing that class X exists in the .NET framework. Communication is key that all team members use the right classes, be they extension methods or some other helper.
As JP has stated, I often see extension methods in some kind of subfolder called Extensions. Hopefully when you state you use my.company.web.utils the namespace is actually Pascal cased?
Even if you put them in a good place there is no 100% guarantee that other developers will use them.