I'm a little surprised somebody with more DFRPG PbP experience hasn't answered this. I myself have only just started playing here. I do have some experience with D&D PbP, though, both running and playing.
First, as to play-by-post vs. play-by-chat. I've never actually done play by chat, but I imagine it goes much faster than play by post. Something more akin to a traditional tabletop RPG. Which is good. But it seems it also requires a bit more prep work. Taking several minutes out of running a chat game to type up the box text for the next scene is probably not going to work well. It also requires that you and your players be available on the same schedule.
Play-by-post, on the other hand, is very slow, but so long as everybody remains active, still quite productive. It requires the same time for typing up intro text for each scene, but you don't have to do it until it comes up. So when the players completely derail your expected plot with their ingenuity or inanity (they always do), you haven't wasted any work.
Second, how to start a game here. Just start an "interest" or "recruitment" thread. It will probably get player responses very quickly. There are always more interested players than fillable player positions due to lack of GMs. And most games seem to have a very short shelf-life. The "City Creation" and "In Character" threads can wait until you have a set of players chosen and/or characters created. Be sure to include all relevant information in your first post of the recruitment thread. Power level (refresh, skills, and skill cap), city (or at least possible cities), any desired aspects or themes (if you have any), number of players you want, how you will select players, restrictions on types of characters, anything else you want.
The chat can be a good way for you and your players to hash out things quickly. Whether it be ideas for new locations and faces or problems with characters. Once there has been a chat where something important has been discussed, I just do a 'select all' then 'copy' and 'paste' into a text document or a reply on these boards. The chat saves a lot of back text (so long as you don't log out). There may be a maximum buffer size, but I have never reached it. The chat is not, however, necessary. There is a message system on the boards so private conversations can occur through that.
