It seems all four of these branches of design relate to each other at one point or another, and one can easily be confused for another by novices or outsiders looking in. Job postings online frequently interchange the terms for job openings, yet explain similar descriptions of job duties.
In reality, there's no difference between jobs with those different titles (except that "web designer" is limited to projects on, well, the web).
In theory, the terms refer to different aspects of the design discipline. Following are three different explanations I've read:
Jesse James Garret draws a line between interaction design and interface design as the degree to which the design has been implemented. Interaction design deals with the structure of the site, while interface design deals with the skeleton (creating concrete representations of the structure created by interaction design). Garrett has a famous diagram that shows how some of the roles are related.