one year ago I submitted an article to a directory. Checking now that article has been removed. If I search on Google some strings, then nothing appear. Can I submit that article to another website? Or that will hurt my ranking on Google?
That's what I mean by "there isn't a lot of value coming from most of them these days." Article directories as a type of backlink have almost no value any more - and the future is even less promising. They still show up as a number, but they don't offer any real power.
If you already have great content that is along the same line, then market that content directly to potentially other interested. That gets you, gradually, in content, freely given backlinks directly your own site's version. This takes a different kind of work - I'd never say it's easy. But the final result is backlinks that really matter, that have staying power, and that give Google the kind of solid signals that they are looking for most of all.
There's just so much you can do with backlinks that you yourself can just place at will. They do not show real engagement with your greater marketplace, and that's what really wins the day.
"Article directories as a type of backlink have almost no value any more..."
Well, here is ONE way to find value in article directories...
Take a COMPETITOR'S article, spin it, and blast it all over the article directories. Heck, don't even bother linking it to your money site. Link it some stranger's site.
Not exactly what they were designed for, but you probably have a better chance of DEVALUING a competitor's article than you would have of creating value from an article of your own.
Another thought is taking your articles and maybe grouping them together and making a free ebook and giving it away. It the info is truly USEFUL to your readers, and if it's FREE, then people will link to the page where you distribute it.
What? I had an excellent idea? I need to write this down on my calendar!
Seriously, I have read some stories by people who were web masters for years and threw in the towel after Panda started to cull sites.
On the other hand, I have talked to some people / looked at some sites that are RUN BY PEOPLE WHO HAVE NO IDEA WHAT SEO IS. In fact, I am not sure they would be able to spell "SEO". They have never even heard of Panda, and I am not sure they EVER look at their traffic stats.
Their sites seem to be doing well and generating money for them.
How do they do it? Well, it ain't rocket surgery; The common thread for those sites is that they are (relatively) unique and they offer value to their visitors.
When you're done with the ebook(.pdf) look into creating a .kml version too if possible, Google loves showing results for varied types of content besides plain text html.
Article directories, feed directories, new/throwaway blogs, new/low trust social profiles etc are all next to useless in providing value for your site now. Look at it this way - if anyone can get a link there Google will not place much value in it. I'm also seeing that you need to have a link on any given page from the moment it is published to get full benefits so finding high ranking pages isn't as useful anymore either.
Plant your seeds and tend to your field, it will grow in time.