What are editorial Images?
Editorial images include photos of newsworthy events, images of places that feature trademarks, images of commercial products, rights protected buildings taken from a public place, images of celebrities or people in the news.
Examples would be:
- Someone drinking a can of Coke or using a clearly identifiable product such as an iPhone
- Someone eating a hamburger outside a well known restaurant with visible signage
- An office building in a city with a corporate logo on it
- A street scene at a festival with lots of people in it
- Celebrity images you took at a sporting event or concert where photography was permitted
Such images would not be accepted by an agency for use as royalty-free stock due to the inclusion of logos or people without releases.
A photo that you take of people in a studio without obtaining a model release would not likely be accepted as an "Editorial Photo". To be considered an editorial photograph, the person(s) would need to be a celebrity, or the photograph would need to depict a newsworthy story or location, preferably a current one.
Images sold as editorial require a different style of description to royalty free  images, particularly a detailed description of the time and place the image was taken. As the primary market for such images is newspapers and magazines such publications need to be able to find and also be confident that the image they are buying is of the correct place and taken at a relevant time. Don't be worried if your image was taken some time ago, while these images might be less relevant for a current story they may be a specific requirement of a story about something that occurred 20 years ago covering changing styles in dress, transport and interior decor etc.
bigstock require the following are included in the image description:
- A clear DESCRIPTION of the image (Who is it and What's happening)
- The DATE the photo was taken
- The PLACE the photo was taken
Some other agencies allow some or all of these details to be added as separate fields when uploading, this aid searching, especially the date fields. Without further specification from an agency I recommend formatting the date as 10 September 2008 and not something like 10/09/08 which can cause problems with the special characters (slashes) and confusion with different date formats around the world (dd/mm/yy vs mm/dd/yy). Depending on your workflow the date and time may also be included by the camera in the EXIF  information, and can be manually added into the IPTC  field "Date Created'.
istockphoto recommend that images of city skylines only be uploaded if they are not more than 3 years old, although many editorial subjects and locations are relatively evergreen (or offer an historic record) there are several subject areas, particularly urban travel locations where images will have a shorter shelf life.
Before their demise luckyoliver offered more money per sale of editorial images, but most of the current agencies are selling editorial licenses at the same price as their standard royalty free stock. It is also to be noted that the editorial market for a large part is time critical and most microstock  sites take several days or a week to review new images.
According to the photoshelter 2008 buyers survey  (caveat that photoshelters' buyers might not be typical microstock buyers) reveals that the possible market for editorial images is a lot less than half of that of other image uses, and that excludes that fact that people working for a magazine or newspaper are not always looking to find editorial images for their publication. Below is a table of respondents (not target market) plotted against image sale:-
There are a lot of places where editorial style photography is popular, the blogosphere for one, but try using istockphoto to find a picture of a high street bank complete with corporate livery to illustrate the current financial situation, you won't; sure you can find financial charts of money, even a generic 'bank', but for a topical news article a real bank is a lot more relevant.
Is microstock entering somewhat uncharted territory here? A place which was previously filled by companies like AP who provided the press with a source of news images. While microstock opened the door for backyard designers to obtain images, I believe it may also change the way that the small time commentator, blogger or your local 'cheap-sheet' obtain their visuals. Editorial microstock is particularly relevant for online media where there is the possibility to electronically source direct from the microstock site, or even create a license model based on cost per image view.
Should I upload?
I've always been skeptical of microstock for editorial. Editorial images are either ephemeral or form an historic archive which may produce only a few sales over their entire life (which might be as long as your lifetime), as such editorial photos are somewhat incompatible with "high-volume low-price" which is the microstock maxim.
Although other agencies have been accepting editorial images for some time, in 2010 istockphoto announced  they would be accepting editorial images. The istock editorial collection contains no celebrity or news shots, purely photos what would otherwise be rejected for containing protected intellectual property. e.g. woman carrying an ipod, a photo of the empire state building, skylines featuring corporate logos. These iconic subjects have the potential to become (reasonably) high sellers, making this style of editorial, perhaps, cost effective to exclusive photographers.
Clearly celebrity, sports and music industry images are very popular, if you already have access to such images then editorial microstock might well be worth some investigation even if it never provides a primary source of income. As ever any comments on this are more than welcome!
Click here for a list of microstock agencies which currently accept editorial images  and other niche Image types