I wanted to try to get a simple SS demo up up and running, just to get a feel for the CMS. I installed SS 2.4.7 successfully, however in reading the requirements for the Simple Guestbook, it lists SpamProtectionModule, ReCaptchaModule, DataObjectModule, and PHPCaptcha module. I decided to start out trying to locate them with a keyword search in the modules section, and none were found. Then I just started with the first one in the alphabet "DataObjectModule", and I can't find that one either.
I suspect I may have made a bad call when I decided to try out SS. Correct me if I'm wrong, but this looks like yet another half-baked CMS, not quite ready for prime time. I'd like to make it work, but not if the basic development infrastructure isn't there.
I've never heard of "DataObjectModule" maybe you mean "DataObjectManager"? But then I don't see that requirement on here http://www.silverstripe.org/simple-guestbook-module/
I generally stick to browsing github in order to get versions of modules - mainly because they are more frequently updated (remember all the silverstripe code is actually on github) also you are morelikely to get in contact with the module owner through that than here on the forum.
And you are quite right module listings on this site (and management in general) requires improvement - and it is getting that improvement right now - http://www.silverstripe.org/2012-google-summer-of-code-students-and-projects-announced/
At least SilverStripe 2.3
Optional PHPCaptcha module
I was able to find DataObjectManager in the Modules section of the website, and ReCaptchaModule as well, but it wasn't clear which versions of SS they were compatible with. I couldn't find PHPCaptcha or SpamProtectionModule.