Does it matter if I only use one article submission site for some of my links or should I mix it up? For example, should I have 20 on ezine OR should I have 10 on ezine and 10 on goarticles, etc?
I do think it's good not to put all your eggs in one basket. However, I think it's not worth dealing with the low-end article directories. GoArticles is at about the boundary of legitimacy. In my case, it did not perform well at all. I wrote an unfavorable review of GoArticles, if you're interested in why I think the site isn't worth your time. When I contacted the site admins sharing my experience with them and offering to share data and expertise with them that might help them improve the site, I got the impression from them that they didn't care. They seem to only want to be able to boast about the number of articles in their directory, and possibly their traffic; but it's sad, because if their site doesn't work for webmasters, they'll never attract the sort of traffic that sites like Buzzle and EzineArticles have. The only straight article directories I would recommend are EzineArticles and Buzzle. Two other sites which are not technically article directories, and require a different approach for each one, but which you also might want to look at, are Squidoo and Gather. HubPages I would avoid; I think HubPages is a scam, at least as far as traffic driving and SEO is concerned; it may be more useful if you are not a webmaster and you use it for generating revenue. I also recently started using ArticlesBase. It's nofollow, but so far it looks promising in terms of driving traffic. But I don't have quite enough data to say conclusively; we'll see how it pans out in the long-run. I also published a single article on TheFreeLibrary.com, and it did not perform well. But I'm cautious about drawing conclusions from a single article. I personally wish that there were more high-quality article directories, but there just aren't. People on these boards are constantly advertising their new article directory but they seem to be adding their site to the low end of the list, not breaking into the higher sites by having editorial integrity. If you want to learn more, you can view my whole reviews on article directories for article marketing.