Currently none, but I remember building several thousand backlinks a day (mostly low quality - social bookmarks, profiles, forums...). That was for a 2 year old websites which already had few dozens of thousands links to it, so I was pretty sure that many links can't harm it.
I aim for 10 links a day with a minimum of 300 a month. Most of the links I build are through articles, social bookmaring and forum posting and I've found that it is very effective for rankings especially when it comes to serache engines like Bing and Yahoo. With Google I make sure the links I build to my site are from sites that are closely related to my business
Usually I submit our site to 50 links and with different link building process. Backlinks with high traffic is the way of Increasing traffic and improving SERP to search engine
Building backlinks depend on how tough your competition is . If you are ranking high on the search engine you need not build links aggressively. But if your sites is ranking low for a particular you need to put more aggressive backlink campaign. To get a good ranking in Serp depends on the strength of the competion involved. I have seen new sites rank on the first page. It all comes down to the strength of your competion. Try to get links from a variety of source. 1. articles 2.blogs commenting 3. profile backlinks 4. Rss 5. directory submission 6.social bookmark The more variety the links are the better. Hope this helps.