The FCC forbids a non-commercial station such as KPSU from issuing “calls to action.” An announcer issues a call to action when he/she asks, urges, or suggests that the listener should perform some task which may result in a for-profit organization to make money. This rule does not apply to non-profit organizations, like KPSU itself. Calls to action include:
You are free to rave about how great a CD or band is; that’s only a “review”, but you may NOT overly encourage listeners to buy the CD. Additionally, you cannot rave about a business establishment. For example, “Waterloo is a great record store” is considered a commercial.
Please note that these phrases refer to a specific band, club, record, and so forth. Non-profit organizations like KPSU are the only entities you can specifically urge people to spend money on. You can, and are encouraged, to tell listeners to attend a benefit for KPSU or purchase KPSU items (such as T-shirts). In short, if it directly makes KPSU or another non-profit organization money, it’s legal. Otherwise, it’s a call to action.
Examples of what is and what isn’t a call to action: