I am a small business owner doing my own seo and have been affected by mr penguin. Luckily for us it only affected certain keywords and resulted in a 30% loss of revenue but I figured out the issue and rectified it quickly. I have come to realise I have been following SEO advice that really works rather than than advice that is 100% Correct as far as google is concerned. As a result I have removed a ton of content from the web and unsubscribed from most of my rss feeds. Going forward I am really only wanting to concentrate on content for our own site and making us squeaky clean. 

The trouble is I am not 100% sure what is meant by “over optimisation”of internal links. Lets say I have a business selling electric razors and their parts (which I don’t) and I am adding 4 or 5 new products a week. I am also creating a couple of blog entries discussing industry related stuff and also creating a couple of entries in our “How To” section describing how to maintain a particular model of razor. Now my real question is if these posts are all good quality information that is truly useful to consumers how much is too much linking to the relevant products?

Currently I might include 2 or 3 anchor text links per piece of content and not to the same product and not using the same keyword eg 
“new braun battery” “braun shaver foils” “shaver foils” 
Over a few different pieces of content I may link to some of these keywords if appropriate. 
Basically I am a bit paranoid now I know I need to be using internal links to help people and spiders and to me the links look totally natural but does thins sound like too much to you?

Sorry that is so long but I really want to get this right going forward.