Unfortunately, you joined iS at a bad time.
New files are mostly being sunk like stones in the Best Match (slightly less fast this past week!), whereas previously they'd get some 'time in the sun' at the top of the search then sink (faster or more gradually) down. Also, the best match algorithm was switched pretty often. In fact, last weekend there was a seismic best match shift, but by late Monday it was back to what it's been for over a year.
In addition, there's the 'curse of the download', whereupon a file getting between 1-9 (some say 1-10) downloads is downshifted even more in the best match.

Personal anecdotes:
Following on a sale yesterday, I checked through and found that it's a search of only 92 files, of a very, and disappointingly low-selling subject.
I have the top three sellers (9, 5, 5), I switched to best match, and out of 92 files, my two with 5 are 91 and 92; the top seller is at 88, with another of mine with 3 at 89. Two of mine with 0 sales are higher.
Technically, it's not so important in a search result of 92, as the buyer may well have set to 100 per page, so look at them all, but in a search of thousands, that is significant.

Of my last 20 sales, the pattern is almost the same as the last time I checked.
6 from 2007
6 from 2008
1 from 2009, no previous sale
1 from 2010, no previous sale
3 from 2011, all editorials
3 from 2012, all editorial
0 from 2013.
NB: there is a slight natural bias in my port towards 2008 at this time, because almost all of my 'seasonal' images and isolations were done that year. Also my uploading is well down this year, as the issues noted above started in late September 2012 and it hardly seemed worth uploading under these cirecumstances.
Having talked about the curse of fewer than 10 dls in best match, 14 of my last 20 have <10 dls, but these are generally low-supply subjects.

If you look at the threads here and on iStock about the PP, many people are reporting good sales there in September and October.

What is PP?

Partner Program: Thinkstock and Photos.com, to which iStock's top buyers are being pushed (by iStock).

3、If the theme of my files are belong to those who are hardly to be sold. If there are any problems of my files?

Your images are simply not stock-oriented. Nature images tend to be high in supply and low in demand and only the very best (and luckiest) will make worthwhile sales. You need to understand the market for stock images before you can produce for it. Before you compose your shot you need to consider who will buy it and what will they use it for.

Quote from: CaptainYoung on November 16, 2013, 03:36

3、If the theme of my files are belong to those who are hardly to be sold. If there are any problems of my files?

Your images are simply not stock-oriented. Nature images tend to be high in supply and low in demand and only the very best (and luckiest) will make worthwhile sales. You need to understand the market for stock images before you can produce for it. Before you compose your shot you need to consider who will buy it and what will they use it for.

Yep.  Plan ahead, not just walk around.

Quote from: gostwyck on November 16, 2013, 06:08

Your images are simply not stock-oriented. Nature images tend to be high in supply and low in demand and only the very best (and luckiest) will make worthwhile sales.

Isn't it surprising IS accepted all those images? What a U turn!

It's ridiculous! This is what happen when there are no upload limits and no QC.  Personally, I'm sick of all these new snapshoters flooding iStock with their big portfolios full of crappy images. 
My advice to any fresher:  Stop flooding the site with all your snapshots!!!You are not going anywhere doing it.

"It's ridiculous! This is what happen when there are no upload limits and no QC.  Personally, I'm sick of all these new snapshoters flooding iStock with their big portfolios full of crappy images. My advice to any fresher:  Stop flooding the site with all your snapshots!!!You are not going anywhere doing it."

as politician I would have worded it more like-

"Due to the easing of the standards on iStock there are more photos being accepted that really don't produce a high commercial value therefore, will be difficult to sell"

Why cut the person's head off? They will get it (via lack of sales on a large amount of images) and make the changes if they want more income. Enough said- time to move on...

It's ridiculous! This is what happen when there are no upload limits and no QC.  Personally, I'm sick of all these new snapshoters flooding iStock with their big portfolios full of crappy images. 
My advice to any fresher:  Stop flooding the site with all your snapshots!!!You are not going anywhere doing it.

I think your comment is out of line.
1. The photographer supplies the kind of pictures that iStock now wants to see. What's your problem? Are you afraid of competing with "snapshots"?
Haven't you heard that iStock is THE place for professionals?

IS have big plans for their collection. They will now be able to compete with Mostphotos or flood Google Drive.
Resistance is futile

2. CaptainYoung's photos are not bad. The compositions are generally quite OK, e.g. this one is quite nice:
http://www.istockphoto.com/stock-photo-29311448-the-road-in-bamboo-forest.php
The main issues are: too many nearly identical photos, the light and colours are not so good and the subject matter which is not popular in microstock.

Do you remember the Galapagos series that was accepted some time ago? Compared to that photographer CaptainYoung is a true master of photography.

"It's ridiculous! This is what happen when there are no upload limits and no QC.  Personally, I'm sick of all these new snapshoters flooding iStock with their big portfolios full of crappy images. My advice to any fresher:  Stop flooding the site with all your snapshots!!!You are not going anywhere doing it."

as politician I would have worded it more like-

"Due to the easing of the standards on iStock there are more photos being accepted that really don't produce a high commercial value therefore, will be difficult to sell"

Why cut the person's head off? They will get it (via lack of sales on a large amount of images) and make the changes if they want more income. Enough said- time to move on...

I prefer my direct and honest words.  The truth is that many "photographers" which have been accepted during the last months, would have never been accepted at iStock before the easing of standars.  I guess nowadays they are accepting anyone.

what you are saying isn't wrong but you haven't found the "best" way of expressing it

1 year ago (or more) instead of 2800 pictures accepted he would have got 280 instead, there are quite a few overexposed and tons of very similar pictures

Quote from: Snufkin on November 16, 2013, 21:49

Do you remember the Galapagos series that was accepted some time ago? Compared to that photographer CaptainYoung is a true master of photography.

Missed the series you're talking about

Sean bought 1 pic from that series for his blog. It was shot by a guy who titles a photo "England" and in the description writes "Edinburgh" .

No minus given just stated that is could have been written in a more polished way - far too blunt in my eyes that's all.   But, overall I am sure they got the tips on why their sales are low- thus taking home some positive notes things.   

I can't stop laughing