My company is currently evaluating several open source projects to help build out a new Software as a Service Platform (historically we never used anything open source) and we were wondering if we needed to disclose Open Source Notices on our actual website, i.e. under footer links  for terms /conditions or  legal or trademarks.  Specifically, we are going to be using an open source project that falls under the Apache 2.0 license and the Apache 2.0 license states (a) You must give any other recipients of the Work or Derivative Works a copy of this License.  We also noticed that several companies, including Netflix, do disclose all open source projects used.  We've also come across some other websites that do the same, however, it appears the majority of sites don't disclose on their website.Any guidance / thoughts would be much appreciated! 
Open Source Notice on a Commercial Website
apache 2.0;open source definition
Some licenses only require notice for code that is distributed, and allows you to use the code on your own machines however the hell you want. Actually, the GPL is one of those licenses! However, you have to remember tricky things, like which licenses are which, the fact that your client-side code is being distributed, and what counts as a derivative work. Since providing notice is generally pretty easy, and everybody is happier when you give credit where credit is due, I'd personally recommend that you err on the side of more notice.