This is just a highly variable matter -- it may not be a decision that is even up to the SC members. There may be dept. protocol, HR protocol, webmaster for the dept. webpage has the flu and didn't have time to post the talks, who knows.
This.
That said, I'm not sure what your question is, OP.
If you're asking a "why" question, then the answer is no one except people on the SC and in the departments can answer. If you're asking a "what happens" question, then you've already answered your question--some departments post the names of job candidates on their Web sites, while others don't.
To agree with t_c again, I don't think you should read anything into the practice.