This is not problem to submit site link on many directories. But the thing is why waste our time while you get good ranking with only few submissions. Work more smarter and less harder.
I think that there is no rule for it..and while submission just the IP address means don't submit on same IP.
There are noting any limit as per understanding, make sure those are only quality not countable. And you can mark now a days google don't recognize free directories.
I think that the quantity has no influence on the whole process. The most important thing here is the quality of the links. More than this, it is essential where the links come from and how trustworthy the other sites are in terms of relevance. As SEO link exchange is one of the most popular techniques of search engine optimization it is important to closely watch where the links are placed. The sites which link to your page are a reflection to your site. Visitors will only follow the link if they consider that page to contain relevant and useful information.
One of the biggest mistakes people make during directory submission is not doing the necessary research. In order to be listed in a directory (which will be approved by another human being), you must prove that you belong in that directory in the category that you have selected. The best way to do this is to select the most appropriate category and to write a concise, accurate description that already resembles descriptions in the targeted directory. Reason? Make it easy for the directory editor to approve your submission. If you are able to imitate the editor's style when describing your web site, you can increase the chance that your site will be accepted and your site description will be unaltered.
I think u can submit around 15 to 20 for a website and choose according to ur need how many u need to submit per day. This leads to quality work without spamming.Also try submitting with reciprocal link
It depends on the directories list you have , If your directories list is very high priority then you can use it.
thanks for the tips. i am so excited to used these kinds of trick. i am newbie here, but not there. i am here just to know how to build some quality backlinks. thanks !