I would only stick to about 100 back links per day. I have noticed my ranking getting better and the quality of people searching my site are staying on longer.
Of course it's OK, if no, nobody will do SEO from such actions. It's good to know that your site making good progress
Yes, SEO is about links and more links! Off-page factors, or labor-intensive link building, are what gets you rankings. In other words, Google® doesn't trust or place much value on what you say is on your site, but they trust what others on the Internet are saying about your website.
I'd say inbound links of good quality have the most beneficial effect and trump almost anything (providing your content is relative to the search of course).