The topic of moblogging fascinates me! However, I don't think many of the sites mentioned have any sort of long-term strategy. The basic schtick is that you have a main homepage with all of the incoming pics streaming in from all phone cam users for anyone to see. That's fine when you only have a few dozen people posting pics on a given day. As these sites grow, they're going to need a way to categorize the photos. Alternatively, photo communities are popping up. With names like "show_your_boobs", "nascar_mania" and "dog_lovers", it's easy to see how your community of interest could more accurately be represented.
Additionally, once the photos are off the front page (or front page of your friends/community list), it pretty much gone forever. If you hit your browser's refresh button, all of those images have been replaced by new ones. The only way to find pics is to look through all images by user, and that will get old quickly for an avid moblogger (10 pics per day * 365 days/year = 3650 pics to look through after just a year). As with any content management system, easy storage of content is only half the battle. Finding it once it's been "archived" is the other half. I won't go on ranting about how poor most content management sites' search facilities are (go ahead, try to find my first LJ comment ever posted on somebody else's journal). I would recommend to developers of these sites to look at Drupal's taxonomy feature for ideas on categorizing content.
Another problem I have with all of the moblogging sites mentioned is that they are photo-centric. That's not a big problem, but most phone cams also support a textual part of the message, or a message that is text only. I would also like to be able to choose the publicity of my content when I publish it (e.g. send a pic to just my friends group, or post to a community instead of my regular moblog).
This informative pointer to an interesting article has turned into a rant on poor design in moblogging sites. I'll end my rant now. Thanks for reading.
To view my own exhibitionism, add yourself to my nullcraftmoblog feed.
(BTW, poisonkitty.net will have the beginnings of a moblogging feature soon. It's installed there, but currently broken. For now, you may use nullcraft.org for your personal moblogging needs.)