I like the idea of aliases. I've seen people often post their PC's name and level in the subject of an IC post. I associate people's avatars and names with their PCs for ease of reading, but when they change their avatar it confuses my primitive human brain. So an alias for posting a pbp IC thread would be great. For now each alias can just link to anywhere on enworld so that players wouldn't have to move an existing character sheet to use it.
In follow-up to my comments
over here, I like the idea of giving a whole post a different background color. If aliases could pick different background colors it would be really helpful for identifying which PC posted what. It would be similar to how the OOC and GM tags call attention to their topic, but organized by PC.
I'm not sure how many different distinct yet still subtle background colors would be available. I'm also not sure how well that would mesh with people wanting to call-out what their PC says.
As an aside, I love how little space the sblocks (or whatever Paizo's board calls them) take up in the alias character sheet on link upthread.
Finally, the dice blocks are really big. Could there be a different formatting option to make them smaller, similar in size to xp posts? I like not having to go to invisible castle to roll, but several rolls in one IC post would be very visually distracting. I'd prefer something like:
1d20+0 -> 3