TinyFeed is a WordPress widget which loads a microblog status feed via Ajax.
The AJAX framework TinyFeed uses is jQuery which works with Internet Explorer 6 and above and Firefox 2 and above, which should be sufficient for most audiences.
Probably not. If your site receives more traffic than the microblogging service, then you might need to be worried, but if your site has more traffic than Twitter or Identi.ca, then you probably have other issues too.
tinyfeed.css file included in the distribution provides a commented framework for theming the widget however you would like.
The time is calculated using the user's timezone.
Because I haven't coded it in yet. I hope to soon include options for how to display the timestamp.
TinyFeed is copyright Joseph Piché, but is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.