A forum isn't necessarily easier, but it is better in a couple of ways.
1. The entire thread from the original question through all the responses is viewable in one place. With the email system, you only see the thread one response at a time. 2. Search. The forum develops a searchable database of questions and answers.
Now, while it's not inherently easier, it doesn't have to be harder either. A decent email notification system would allow users to receive notices of new threads started as well as replies to existing threads. Ideally, it could email the entire first post but no one of the replies unless the user subscribed to that thread itself. So, we could get the initial question via email as we do now, but not get any replies unless we subscribed to that thread. A 'subscribe' link could be added to the email itself.
Unfortunately, the system as we have it now fails to provide the benefits of a forum listed above due to the use of emailed posts and responses. Threads are a jumbled mess and many times incomplete, making the search function of limited value. Even this valuable discussion on the nature of the group will be buried inside a thread on ISDX (which never got answered) which was converted to a thread on screw threads.
As it is now, it works better as an email list, but as more members log on and post online, even that is becoming diluted. Unless something is changed, I see a day coming where I will no longer use PTC/User.
With regard to your last comment, that was coming when we lost the e-mail and forum moderator and PTC failed to appoint another. Personally, I prefer the e-mail option but like "shown" and "created" dimensioning, this argument will never end.
FYI...using google desktop is very useful for search (assuming you don't delete the emails). I rarely, if ever, use the website search since GD finds everything I need, even if the thread is broken up into multiple emails.