I feature that i think is kind of strange to be missing is to have more than just a text based forum signature.
For a lot of communities for groups such as YouTubers, Gamers etc people often use forums to communicate and leave links to their channels, projects, teams and social media and thats something a Dolphin powered site doesn't offer.
If would be nice to be able to add links and images to my signature on my site and allow other to do the same.
As well as that Admins can also have to power to limit things such as links. (eg, only allow 1 link and 1 image in either png, jpg or gif formats and no larger than 1024 x 400 px)
This was something that could sort of be done in older versions but had no limits and forced the user to know html.
