There is a lot of information you could post about your department. Focus on what makes you unique.
If your website doesn’t sufficiently differentiate you from others—“others” might be other majors on campus or similar programs at other universities—you are much less likely to generate the interest you are seeking.
What makes your department unique may mean different things to different audiences:
Potential undergraduates may be most interested in your internship program or job placement rates
Potential graduate students may be more interested in research opportunities
Colleagues at other institutions may want to know about any journals published by your department
The unique aspects of your department that you choose to highlight will therefore depend on your goals. Examine your goals, then decide what needs to be highlighted.