Why was http://www.imcdb.org/vehicle.php?id=586198 (a Nissan or Datsun pickup truck in the background of a closeup of Bernard Stevens on his motorcycle in Northern Exposure episode 1-8) deleted?

Also, the site needs an option to show added vehicles (not just comments and pictures--which doesn't actually show one's pictures but just annoyingly links to the series) in one's profile and get email notification if a submission is approved/denied (and why).

Possibly it was not worth keeping, if it was too background.
If you still have the picture you could re-upload it just in the comments of the bike.

There are a few hundreds of vehicles added each day. For movies usually they are added to the latest completed list at the top (which sometimes does not even cover 24h if many are added). For series it is more difficult to follow indeed. That's a point that we plan to improve in the future, but due to the large amount of vehicles added it is difficult to see all what's new. If you want to follow a particular series or make, you can still sort the vehicles list by "date added", then you'll have the newly added ones at the beginning of the list.

Once vehicles are validated there is no link between who added it and the vehicle itself. So the site can't list the vehicles added by someone. Also, it has not much interest to know that, it seems
However following which of your own contributions were validated or rejected is useful and will be added in the future, we are working on that.

Too background? I thought the whole point of this site is to identify cars and other vehicles (like some tracked vehicles and some kinds of motorhomes, but not snowmobiles or motorhome trailers for some unknown yet inconsistent reason)?

We cannot list _all_ vehicles, so we have to put a limit somewhere.
At first it was only cars with a role.
Since some time now it is also background vehicles that are visible enough (good pic and/or long time and/or some link with the movie).

Why can't all vehicles be listed? The database isn't paper-based so it's not like there isn't enough physical space, and server space shouldn't be a problem to hold, what, maybe another few GB at most for low-res pictures, text, and database fields? See http://meta.wikimedia.org/wiki/Wiki_is_not_paper for more info.

Wiki is not paper, but you still can't create an article for anything and everything... http://en.wikipedia.org/wiki/Wikipedia:Notability

Yes but this site isn't as anal as Wikipedia in terms of notability. Vehicles here don't require references (though I have provided one for a Harley in Northern Exposure). My point is, limiting included vehicles is silly when a site purports to being a database for vehicles (especially cars, which is what I submitted and was deleted).

- If there are millions of vehicles listed, the interesting ones will be even more hidden in that. That's one of the big problems of the current site, why would we increase it for cars that no one cares about?
- The site is not designed to handle huge lists. See big pages like Top Gear, Alarm Cobra, etc.
- The point/purpose of the site is listing cars with role in movies. The background ones are just a plus, like the documentaries and TV shows, hence why these have limits.

What's "interesting" to one person may not be "interesting" to another person. Who is to say which vehicles are included and which are not? It's all relative. Don't be a wiktator (wiki dictator). "Top Gear" is a vehicle-specific show so of course it will have a huge list of vehicles. Who is to say that obscure Nissan Datsun pickup truck isn't interesting to someone who finds it fascinating it was shown in a specific episode of a specific television series, for example? Maybe it was someone's first vehicle and, combined with, say, a fond memory of watching that particular episode, it sparks certain memories?

If the site can't handle huge lists it isn't designed well enough and should be redesigned because it's only going to get more vehicles, not less. Databases should be able to expand and grow with ease if they are designe competently initially. Perhaps moving towards MediaWiki would be a better platform, like the Internet Movie Plane Database uses.

As I said, we have to put a limit somewhere.
People also wanted trains, planes, etc.
edit: and I see you just asked that... http://www.imcdb.org/movie.php?id=98878#Comment1350660
We can't list all.
We are not a company with hundreds of people working on the site like Facebook and other huge sites with "unlimited" resources.
I was working alone on my free-time on the site. Now for the redesigned version we are two people, still working on our free-time, from time to time. And we do not plan to include more types of contents. Just try to organise better what is currently accepted, since it is already not well enough organized.

Hence the reason to go to a more open, MediaWiki-style site that allows anyone to edit content...

I do not see how that would help. The problem is not that we lack people for making the contents: we lack people for writing the software itself.

MediaWiki is already written. You simply need to install it and set it up. See the Internet Movie Plane Database and Wikipedia for examples of websites that use MediaWiki.

A wiki isn't very good for such kind of site.
I find IMPDb is much more difficult to use than IMCDb (both for visitors and for contributors).