Being all about a personal viewpoint, a liveblog is only editable by the author. They are most often a detailed walkthrough of a work, done in installments. No special invitation is needed for you to start your liveblog.
We have moderators that have the power to delete stuff that needs deleting. They also have edit powers for the liveblogs. If they come across an installment that is spelled badly and has crappy grammar, they'll most likely delete it, not fix it. Your spelling and your grammar are your responsibility in your liveblog. We aren't into hosting crappily written stuff.
Have fun with it. Both geeked-out nerdy fangasms and curmudgeonly mutterings are expected. As long as it isn't boring.