if your site has enough visitors and you don't waste your time
the whole point of your site is to funnel in visitors from your marketing/promotions and for ppl to enjoy the blog/information on your site as well as your service and products
I use linkshare and you can approach companies on your own as well
I have samash on my site because alot of artists/producers come to my site
click the QR Code in my sig and look at the right side of my site for some of the companies I have on there...