As I have mentioned, a personal, face to face meeting in a job fair is always preferable vs online job searching, at least if the engineers you send to handle interviews are any good with people skills. If all you want is a tech guy that you can lock up in a cubicle in the corner of the office and have him grind out assigned projects, then I guess I would agree that an online job board would be the best choice since no people skills will be required to apply online.
I would much rather hire someone who can contribute, not just the skills that you are looking for now, but add value to your company in the future. I know that my thinking is old fashioned and not acceptable in today’s business world where the average tenure of a technical or computer type guy or employee may be only 2 or 3 years.
Also, keep in mind that a student who attends a job fair may be able to get in front of 2 or 3 companies in a short period of time, maybe more if they are lucky. I would think that type of face time is much more preferable than just having your HR person do a keyword on resume search and basically choosing a candidate at random.. As a plus, a face to face meeting gives a student a little interviewing practice. This job fair may be the first real world exposure a student gets in their quest for a career type job, rather than just a part time or summer job interview where the manager asks if the student has a pulse.
To me the online job search is kind of like reaching into a barrel full of online resumes and pulling one or two out for consideration. Hiring the right people is sometimes a make or break decision for a company. Chose right and projects get done correctly, on time. Chose wrong and all plans go out the window, plus how much may have to be spent correcting mistakes? How much are you going to be paying a new hire? $50,000? $100,000? More? Are you really that worried about spending several hundred or perhaps a few thousand on recruiting?