Well, title does say it all, but I'll give a background to whom might interest.
This one day I was going the subway and a whole line stopped because of some literally freak accident. Everyone in there were taking pictures and most certainly at least few people there tweeted about it (I haven't checked, but I think there's no need to). So, most likely that became a trend, maybe even the most popular one for certain region.
Had I knew about this 30 minutes before I left home (and the accident was there for like 2 or 4 hours), it would have saved me a good half day walking the rest of the path.
So, just few moments ago I thought, "well, with all this technology, can't I get automatically notified on this kind of local event? Is it the only way to know it before hand by updating and actively browsing and checking Twitter?" Thus, this question.
Anyone got something?
Good notifications system I can think of are email and calendar-like.