Re: Speedposting or having a post overlap others, in my rp we generally just 'call' the next post within the ooc to allow others to know not to post for the next hour or so whilst we write a post, and/or post a 'WIP' in the IC to obviously let everyone know the IC post is a work in progress. 

I dislike collabing or the idea of using titanpad or otherwise within a small group as opposed to just getting on with the IC posting itself. All it takes is for one person to slow things down within a collab and it hinders and slows down the rest too (not to mention the difficulties involved with seperate timezones and the like), whereas if you've got the IC actually continually moving it makes it easier for every other player to respond to.

As for larger group/character roleplays, yeah, multiple groups/scenes are always handy and something I strive to set up. Makes inter-character interaction and scenes better and more interesting whilst also making plot development easier too.