There is a tremendous amount of bias and selective memory involved in recruiting. The tracking system and notes help fight this a lot. General comments like "Math majors can't do recursion" or "We do best with employee referrals" can be systemically checked.

Perhaps the only thing I would add to the process is I like to keep feedback private until it's decision time. If there are 4 people interviewing, they should have assigned roles in advance, and submit feedback anonymously first. Otherwise everyone just agrees with the boss.

Is it OK to store candidates personal information in a free SAAS?

The fact someone has applied to you could be highly confidential.

When a board is private, only those users added as members to the board can view or edit it.

Thats not what he meant.

What he meant is that you are putting the private data of the applicants on the internet, on the servers of another company. I too find this highly dubious.

That's how every candidate tracking system works. Paid or otherwise.

Not everything has to be a web application, and not all web applications have to be hosted by a third party.