My question is would you have to give the source to Bob in marketing and or the customer you gave the sample too?Yes. Unless you want to extend them a written offer instead, which means that offer must be valid for anyone.
If I wrote a web based CMS and put it on the internet would I have to release the source code?If you _wrote_ it (i.e. the copyright is in your name), you are not obliged to do anything. The obligation is only incurred when you redistribute a copy of others' code under the GPL. If it is someone else's web app that you are making copies of and distributing, then unless you have extra permissions from them, you have to abide by the GPL; it is the only thing that gives you the right to redistribute that particular code.
I am just wondering have they modified the GPL to cover things like web apps yet?No, not in the way you are probably thinking of. With a web app or other thin client environment, the program is on the server side and is never distributed to the client; only a presentation layer is sent to the client. In this case, what have you distributed? Certainly the author of the CMS system cannot claim a copyright on the generated pages. And even if the CMS itself was licensed under the GPL, you are free to ignore the GPL because you are distributing no portion of it to the people accessing your site via a thin client (i.e. a web browser).