Is it possible to submit to too many directories? I'm not talking about a large number in a short amount of time. I would like to know if it does any good or could it cause harm for a site/blog that's several years old with lots of links to continue to submit to directories?
it causes good.because you are likely to get pr update as well as traffic update if you submit to high pr directories.
Submitting the site to directories is a tedious work that requires time and efforts. There is a considerable debate about whether the effort required gaining back links from Free Web Directories is worth the payback. In fact, you may request links from hundreds of free directories, but only receive dozens of actual links, often from Page Rank 0 pages. The frequency depends on several factors: 1) how old the domain is, 2) what PageRank the domain has, 3) the quantity and value of back links to the domain currently indexed by the search engine.
You can submit as many as you can as long you are submitting to those quality directories. Another thing, avoid submitting with penalized directory