...member signatures.
Even though you can have a signature in your profile, it will not be visible below your posts. This is because signatures attached to each post can be very distracting and repetitive when reading a topic. Upon reading a post, the signature looks almost like the next post or even a commercial banner depending on the type of the signature. Unwillingly the brain will start reading it and it can be very tiring and distractive from the main subject after a while.
There are some thoughts to put the signatures in the right side of each post below the posters' names. Perhaps it will be added in the future. Meanwhile, feel free to add your signatures in your profiles if you wish. They are still visible in the profile page.
...topic subscriptions.
Being able to subscribe to a topic or an entire forum is great! Well, at first. The more the forums grow, the more useless this function becomes. Lots of old users and/or dead emails start to clog up the system. Subscription works fine if you have for example a podcast where the "content" is not on the main site, although even there an RSS feed is a lot better.
Another issue with this function is that because"users" are inherently "lazy" (those who build software know what it means), this function will help keeping them away from the website and not visiting it often. We have nothing against such users, we do not mind them at all but these kinds of "remote" users are not something we actively seek or care about. That's why the subscription function is disabled. If you care about this place, you should be actively visiting it and not "remotely".

...private messaging.
This too will start to clog up the system after a while. Lots of junk gathers in the database. For private talk between members, they can just visit each other's profiles and use whatever is there like a website or an instant messaging address. For a group chat? Just start a thread!


...it is not possible to edit your posts.
This is to prevent "rogue elements" to delete data or in case someone's account gets hacked. There is also the issue of quotes where if someone quotes someone else and the original post gets edited, the quote could suddenly become wrong. Unlike 1984, the past cannot be changed here!
Addendum:
If our Web site seems to not be working properly due to you using an old version of the browser of your choice, we do not care. At all. For example, if you feel that it is prudent of you to stay in an old Internet Explorer version, say 6.x, don't come nagging to us that this Web site is not working in it. Update your browser. In such cases, it is not the Web site which is broken but it is you that are breaking the Web. Seriously.